# WBS,  severity,  frequency
#concept
              2,         1,          0
              2,         2,          7
              2,         3,         54
              2,         4,         11
              2,         5,          2
# requirements
              3,         1,          1
              3,         2,         70
              3,         3,        874
              3,         4,        435
              3,         5,        133
# design
              4,         1,          0
              4,         2,         18
              4,         3,        275
              4,         4,        129
              4,         5,         25
# implement
              5,         1,          1
              5,         2,        59 
              5,         3,        364
              5,         4,        282
              5,         5,         76
# test
              6,         1,          1
              6,         2,         10
              6,         3,        361
              6,         4,        271
              6,         5,         41