 year month     decimal     average       trend
  1980     1    1980.042      338.45      337.82
  1980     2    1980.125      339.17      338.12
  1980     3    1980.208      339.49      338.14
  1980     4    1980.292      339.87      338.25
  1980     5    1980.375      340.30      338.78
  1980     6    1980.458      339.86      339.08
  1980     7    1980.542      338.32      339.17
  1980     8    1980.625      337.11      339.37
  1980     9    1980.708      336.95      339.33
  1980    10    1980.792      337.71      339.06
  1980    11    1980.875      338.83      339.17
  1980    12    1980.958      339.55      339.32
  1981     1    1981.042      340.10      339.47
  1981     2    1981.125      340.66      339.61
  1981     3    1981.208      341.29      339.94
  1981     4    1981.292      341.57      339.96
  1981     5    1981.375      341.28      339.76
  1981     6    1981.458      340.48      339.70
  1981     7    1981.542      339.10      339.95
  1981     8    1981.625      337.98      340.24
  1981     9    1981.708      337.86      340.24
  1981    10    1981.792      338.95      340.30
  1981    11    1981.875      340.06      340.39
  1981    12    1981.958      340.64      340.42
  1982     1    1982.042      341.27      340.66
  1982     2    1982.125      341.86      340.80
  1982     3    1982.208      342.13      340.75
  1982     4    1982.292      342.42      340.81
  1982     5    1982.375      342.27      340.75
  1982     6    1982.458      341.39      340.63
  1982     7    1982.542      339.66      340.51
  1982     8    1982.625      338.02      340.30
  1982     9    1982.708      338.08      340.44
  1982    10    1982.792      339.53      340.88
  1982    11    1982.875      340.85      341.19
  1982    12    1982.958      341.68      341.45
  1983     1    1983.042      342.28      341.62
  1983     2    1983.125      342.65      341.61
  1983     3    1983.208      342.94      341.60
  1983     4    1983.292      343.41      341.83
  1983     5    1983.375      343.72      342.20
  1983     6    1983.458      343.41      342.62
  1983     7    1983.542      342.05      342.82
  1983     8    1983.625      340.54      342.75
  1983     9    1983.708      340.48      342.89
  1983    10    1983.792      341.67      343.08
  1983    11    1983.875      342.71      343.06
  1983    12    1983.958      343.37      343.15
  1984     1    1984.042      344.22      343.56
  1984     2    1984.125      344.73      343.73
  1984     3    1984.208      344.85      343.50
  1984     4    1984.292      345.09      343.46
  1984     5    1984.375      345.24      343.70
  1984     6    1984.458      344.46      343.71
  1984     7    1984.542      343.10      343.91
  1984     8    1984.625      342.13      344.40
  1984     9    1984.708      342.03      344.47
  1984    10    1984.792      342.89      344.28
  1984    11    1984.875      344.07      344.38
  1984    12    1984.958      344.91      344.63
  1985     1    1985.042      345.26      344.58
  1985     2    1985.125      345.72      344.70
  1985     3    1985.208      346.57      345.25
  1985     4    1985.292      346.85      345.24
  1985     5    1985.375      346.67      345.10
  1985     6    1985.458      346.17      345.39
  1985     7    1985.542      344.87      345.68
  1985     8    1985.625      343.39      345.69
  1985     9    1985.708      343.33      345.77
  1985    10    1985.792      344.57      345.97
  1985    11    1985.875      345.71      346.03
  1985    12    1985.958      346.45      346.16
  1986     1    1986.042      347.01      346.33
  1986     2    1986.125      347.24      346.25
  1986     3    1986.208      347.62      346.29
  1986     4    1986.292      348.15      346.53
  1986     5    1986.375      348.25      346.68
  1986     6    1986.458      347.68      346.91
  1986     7    1986.542      346.22      347.05
  1986     8    1986.625      344.86      347.14
  1986     9    1986.708      344.76      347.16
  1986    10    1986.792      345.93      347.31
  1986    11    1986.875      347.25      347.59
  1986    12    1986.958      347.68      347.41
  1987     1    1987.042      347.92      347.14
  1987     2    1987.125      348.48      347.39
  1987     3    1987.208      349.22      347.80
  1987     4    1987.292      349.91      348.23
  1987     5    1987.375      350.20      348.62
  1987     6    1987.458      349.41      348.75
  1987     7    1987.542      347.89      348.86
  1987     8    1987.625      346.63      349.00
  1987     9    1987.708      346.67      349.12
  1987    10    1987.792      347.93      349.33
  1987    11    1987.875      349.20      349.53
  1987    12    1987.958      350.16      349.86
  1988     1    1988.042      350.89      350.11
  1988     2    1988.125      351.47      350.39
  1988     3    1988.208      351.86      350.40
  1988     4    1988.292      352.32      350.54
  1988     5    1988.375      352.46      350.83
  1988     6    1988.458      351.77      351.06
  1988     7    1988.542      350.31      351.29
  1988     8    1988.625      349.11      351.55
  1988     9    1988.708      349.28      351.79
  1988    10    1988.792      350.46      351.89
  1988    11    1988.875      351.64      352.00
  1988    12    1988.958      352.52      352.24
  1989     1    1989.042      353.04      352.23
  1989     2    1989.125      353.48      352.38
  1989     3    1989.208      354.03      352.60
  1989     4    1989.292      354.41      352.62
  1989     5    1989.375      354.25      352.56
  1989     6    1989.458      353.31      352.60
  1989     7    1989.542      351.55      352.57
  1989     8    1989.625      350.20      352.68
  1989     9    1989.708      350.53      353.07
  1989    10    1989.792      351.80      353.24
  1989    11    1989.875      352.98      353.32
  1989    12    1989.958      353.84      353.53
  1990     1    1990.042      354.39      353.65
  1990     2    1990.125      354.80      353.74
  1990     3    1990.208      355.11      353.69
  1990     4    1990.292      355.44      353.66
  1990     5    1990.375      355.35      353.68
  1990     6    1990.458      354.26      353.60
  1990     7    1990.542      352.65      353.72
  1990     8    1990.625      351.52      354.04
  1990     9    1990.708      351.73      354.25
  1990    10    1990.792      353.13      354.52
  1990    11    1990.875      354.36      354.65
  1990    12    1990.958      355.09      354.63
  1991     1    1991.042      355.65      354.89
  1991     2    1991.125      356.05      354.94
  1991     3    1991.208      356.61      355.18
  1991     4    1991.292      357.14      355.38
  1991     5    1991.375      357.02      355.39
  1991     6    1991.458      356.13      355.52
  1991     7    1991.542      354.45      355.55
  1991     8    1991.625      352.94      355.46
  1991     9    1991.708      352.86      355.39
  1991    10    1991.792      353.89      355.28
  1991    11    1991.875      355.04      355.29
  1991    12    1991.958      355.88      355.38
  1992     1    1992.042      356.46      355.67
  1992     2    1992.125      356.83      355.70
  1992     3    1992.208      357.20      355.73
  1992     4    1992.292      357.67      355.87
  1992     5    1992.375      357.73      356.09
  1992     6    1992.458      356.82      356.22
  1992     7    1992.542      355.12      356.26
  1992     8    1992.625      353.53      356.10
  1992     9    1992.708      353.45      356.01
  1992    10    1992.792      354.71      356.11
  1992    11    1992.875      355.89      356.14
  1992    12    1992.958      356.65      356.16
  1993     1    1993.042      357.12      356.28
  1993     2    1993.125      357.47      356.32
  1993     3    1993.208      357.88      356.43
  1993     4    1993.292      358.32      356.56
  1993     5    1993.375      358.25      356.61
  1993     6    1993.458      357.23      356.56
  1993     7    1993.542      355.61      356.63
  1993     8    1993.625      354.33      356.80
  1993     9    1993.708      354.38      356.96
  1993    10    1993.792      355.62      357.10
  1993    11    1993.875      356.84      357.18
  1993    12    1993.958      357.74      357.36
  1994     1    1994.042      358.36      357.51
  1994     2    1994.125      358.90      357.75
  1994     3    1994.208      359.24      357.78
  1994     4    1994.292      359.58      357.80
  1994     5    1994.375      359.60      357.93
  1994     6    1994.458      358.66      357.94
  1994     7    1994.542      357.16      358.14
  1994     8    1994.625      355.95      358.47
  1994     9    1994.708      355.90      358.56
  1994    10    1994.792      357.13      358.67
  1994    11    1994.875      358.60      358.95
  1994    12    1994.958      359.48      359.07
  1995     1    1995.042      360.03      359.18
  1995     2    1995.125      360.50      359.38
  1995     3    1995.208      360.97      359.59
  1995     4    1995.292      361.43      359.73
  1995     5    1995.375      361.32      359.71
  1995     6    1995.458      360.49      359.79
  1995     7    1995.542      358.86      359.85
  1995     8    1995.625      357.57      360.06
  1995     9    1995.708      357.90      360.51
  1995    10    1995.792      359.28      360.74
  1995    11    1995.875      360.63      360.90
  1995    12    1995.958      361.50      361.03
  1996     1    1996.042      362.01      361.08
  1996     2    1996.125      362.36      361.18
  1996     3    1996.208      362.68      361.25
  1996     4    1996.292      363.00      361.28
  1996     5    1996.375      363.15      361.55
  1996     6    1996.458      362.75      362.10
  1996     7    1996.542      361.48      362.53
  1996     8    1996.625      359.96      362.48
  1996     9    1996.708      359.57      362.18
  1996    10    1996.792      360.55      362.03
  1996    11    1996.875      361.66      361.95
  1996    12    1996.958      362.52      362.07
  1997     1    1997.042      363.15      362.20
  1997     2    1997.125      363.50      362.32
  1997     3    1997.208      363.88      362.46
  1997     4    1997.292      364.37      362.68
  1997     5    1997.375      364.42      362.85
  1997     6    1997.458      363.52      362.88
  1997     7    1997.542      361.82      362.87
  1997     8    1997.625      360.27      362.78
  1997     9    1997.708      360.27      362.88
  1997    10    1997.792      361.80      363.27
  1997    11    1997.875      363.49      363.75
  1997    12    1997.958      364.55      364.08
  1998     1    1998.042      365.05      364.12
  1998     2    1998.125      365.37      364.21
  1998     3    1998.208      365.84      364.44
  1998     4    1998.292      366.46      364.79
  1998     5    1998.375      366.70      365.16
  1998     6    1998.458      366.12      365.51
  1998     7    1998.542      364.66      365.72
  1998     8    1998.625      363.59      366.10
  1998     9    1998.708      363.87      366.46
  1998    10    1998.792      365.22      366.65
  1998    11    1998.875      366.49      366.72
  1998    12    1998.958      367.33      366.83
  1999     1    1999.042      367.98      367.05
  1999     2    1999.125      368.36      367.22
  1999     3    1999.208      368.74      367.36
  1999     4    1999.292      369.13      367.49
  1999     5    1999.375      369.06      367.55
  1999     6    1999.458      368.19      367.61
  1999     7    1999.542      366.47      367.52
  1999     8    1999.625      365.13      367.60
  1999     9    1999.708      365.32      367.88
  1999    10    1999.792      366.63      368.05
  1999    11    1999.875      367.92      368.13
  1999    12    1999.958      368.75      368.20
  2000     1    2000.042      369.26      368.35
  2000     2    2000.125      369.55      368.41
  2000     3    2000.208      369.87      368.48
  2000     4    2000.292      370.22      368.56
  2000     5    2000.375      370.13      368.59
  2000     6    2000.458      369.19      368.66
  2000     7    2000.542      367.76      368.91
  2000     8    2000.625      366.59      369.13
  2000     9    2000.708      366.57      369.12
  2000    10    2000.792      367.82      369.19
  2000    11    2000.875      369.20      369.35
  2000    12    2000.958      370.01      369.42
  2001     1    2001.042      370.52      369.64
  2001     2    2001.125      370.98      369.83
  2001     3    2001.208      371.37      369.96
  2001     4    2001.292      371.71      370.04
  2001     5    2001.375      371.63      370.11
  2001     6    2001.458      370.71      370.18
  2001     7    2001.542      369.30      370.43
  2001     8    2001.625      368.15      370.65
  2001     9    2001.708      368.19      370.72
  2001    10    2001.792      369.54      370.92
  2001    11    2001.875      370.90      371.09
  2001    12    2001.958      371.82      371.28
  2002     1    2002.042      372.34      371.38
  2002     2    2002.125      372.72      371.49
  2002     3    2002.208      373.22      371.71
  2002     4    2002.292      373.56      371.81
  2002     5    2002.375      373.55      371.97
  2002     6    2002.458      372.69      372.14
  2002     7    2002.542      371.26      372.41
  2002     8    2002.625      370.18      372.73
  2002     9    2002.708      370.49      373.11
  2002    10    2002.792      371.76      373.24
  2002    11    2002.875      373.12      373.39
  2002    12    2002.958      374.13      373.66
  2003     1    2003.042      374.78      373.78
  2003     2    2003.125      375.31      374.01
  2003     3    2003.208      375.75      374.18
  2003     4    2003.292      376.22      374.43
  2003     5    2003.375      376.36      374.75
  2003     6    2003.458      375.51      374.95
  2003     7    2003.542      373.96      375.11
  2003     8    2003.625      372.73      375.32
  2003     9    2003.708      372.93      375.60
  2003    10    2003.792      374.23      375.75
  2003    11    2003.875      375.51      375.82
  2003    12    2003.958      376.34      375.90
  2004     1    2004.042      376.99      376.02
  2004     2    2004.125      377.52      376.22
  2004     3    2004.208      377.94      376.35
  2004     4    2004.292      378.30      376.51
  2004     5    2004.375      378.23      376.63
  2004     6    2004.458      377.35      376.80
  2004     7    2004.542      375.81      376.99
  2004     8    2004.625      374.36      377.00
  2004     9    2004.708      374.25      376.92
  2004    10    2004.792      375.57      377.07
  2004    11    2004.875      377.02      377.31
  2004    12    2004.958      378.00      377.51
  2005     1    2005.042      378.59      377.63
  2005     2    2005.125      379.03      377.73
  2005     3    2005.208      379.66      378.06
  2005     4    2005.292      380.17      378.35
  2005     5    2005.375      380.27      378.63
  2005     6    2005.458      379.43      378.84
  2005     7    2005.542      377.75      378.91
  2005     8    2005.625      376.51      379.15
  2005     9    2005.708      376.59      379.28
  2005    10    2005.792      377.92      379.47
  2005    11    2005.875      379.40      379.73
  2005    12    2005.958      380.38      379.90
  2006     1    2006.042      381.10      380.11
  2006     2    2006.125      381.75      380.40
  2006     3    2006.208      382.16      380.54
  2006     4    2006.292      382.48      380.65
  2006     5    2006.375      382.43      380.76
  2006     6    2006.458      381.56      380.94
  2006     7    2006.542      379.87      381.07
  2006     8    2006.625      378.31      381.01
  2006     9    2006.708      378.42      381.18
  2006    10    2006.792      379.82      381.40
  2006    11    2006.875      381.18      381.51
  2006    12    2006.958      382.15      381.67
  2007     1    2007.042      382.82      381.82
  2007     2    2007.125      383.35      381.97
  2007     3    2007.208      383.81      382.17
  2007     4    2007.292      384.10      382.27
  2007     5    2007.375      383.96      382.32
  2007     6    2007.458      383.08      382.51
  2007     7    2007.542      381.39      382.64
  2007     8    2007.625      380.13      382.86
  2007     9    2007.708      380.50      383.27
  2007    10    2007.792      381.89      383.44
  2007    11    2007.875      383.21      383.49
  2007    12    2007.958      384.21      383.70
  2008     1    2008.042      384.97      383.97
  2008     2    2008.125      385.49      384.11
  2008     3    2008.208      385.90      384.29
  2008     4    2008.292      386.31      384.50
  2008     5    2008.375      386.29      384.67
  2008     6    2008.458      385.35      384.79
  2008     7    2008.542      383.82      385.13
  2008     8    2008.625      382.50      385.28
  2008     9    2008.708      382.29      385.04
  2008    10    2008.792      383.43      384.91
  2008    11    2008.875      384.92      385.14
  2008    12    2008.958      386.01      385.46
  2009     1    2009.042      386.77      385.74
  2009     2    2009.125      387.21      385.79
  2009     3    2009.208      387.43      385.78
  2009     4    2009.292      387.73      385.92
  2009     5    2009.375      387.71      386.12
  2009     6    2009.458      386.74      386.24
  2009     7    2009.542      384.87      386.26
  2009     8    2009.625      383.50      386.34
  2009     9    2009.708      383.71      386.44
  2009    10    2009.792      385.24      386.67
  2009    11    2009.875      386.77      386.95
  2009    12    2009.958      387.70      387.14
  2010     1    2010.042      388.44      387.44
  2010     2    2010.125      389.14      387.75
  2010     3    2010.208      389.47      387.84
  2010     4    2010.292      389.76      387.96
  2010     5    2010.375      389.72      388.13
  2010     6    2010.458      388.80      388.30
  2010     7    2010.542      387.21      388.58
  2010     8    2010.625      386.09      388.87
  2010     9    2010.708      386.53      389.22
  2010    10    2010.792      388.09      389.52
  2010    11    2010.875      389.50      389.68
  2010    12    2010.958      390.22      389.68
  2011     1    2011.042      390.74      389.68
  2011     2    2011.125      391.19      389.77
  2011     3    2011.208      391.50      389.88
  2011     4    2011.292      391.89      390.09
  2011     5    2011.375      391.90      390.28
  2011     6    2011.458      390.97      390.47
  2011     7    2011.542      389.04      390.41
  2011     8    2011.625      387.73      390.50
  2011     9    2011.708      388.15      390.86
  2011    10    2011.792      389.73      391.20
  2011    11    2011.875      391.10      391.30
  2011    12    2011.958      391.90      391.39
  2012     1    2012.042      392.42      391.39
  2012     2    2012.125      393.02      391.61
  2012     3    2012.208      393.54      391.91
  2012     4    2012.292      393.81      391.99
  2012     5    2012.375      393.69      392.10
  2012     6    2012.458      392.66      392.17
  2012     7    2012.542      390.88      392.26
  2012     8    2012.625      389.77      392.54
  2012     9    2012.708      390.37      393.08
  2012    10    2012.792      391.96      393.42
  2012    11    2012.875      393.37      393.57
  2012    12    2012.958      394.19      393.65
  2013     1    2013.042      394.90      393.87
  2013     2    2013.125      395.52      394.10
  2013     3    2013.208      396.07      394.44
  2013     4    2013.292      396.53      394.71
  2013     5    2013.375      396.58      395.00
  2013     6    2013.458      395.80      395.30
  2013     7    2013.542      394.28      395.66
  2013     8    2013.625      393.08      395.84
  2013     9    2013.708      393.07      395.78
  2013    10    2013.792      394.34      395.79
  2013    11    2013.875      395.77      395.97
  2013    12    2013.958      396.72      396.19
  2014     1    2014.042      397.42      396.40
  2014     2    2014.125      397.85      396.43
  2014     3    2014.208      398.10      396.48
  2014     4    2014.292      398.43      396.61
  2014     5    2014.375      398.49      396.90
  2014     6    2014.458      397.52      397.02
  2014     7    2014.542      395.89      397.27
  2014     8    2014.625      394.79      397.56
  2014     9    2014.708      394.90      397.61
  2014    10    2014.792      396.18      397.63
  2014    11    2014.875      397.69      397.90
  2014    12    2014.958      398.62      398.08
  2015     1    2015.042      399.31      398.29
  2015     2    2015.125      400.01      398.59
  2015     3    2015.208      400.59      398.96
  2015     4    2015.292      401.24      399.41
