Also interesting to see these graphs: http://jama.jamanetwork.com/article.aspx?articleid=1906616 From: http://jama.jamanetwork.com/article.aspx?articleid=2434682&utm_source=silverchair+information+systems&utm_medium=email&utm_campaign=master:jamalatestissuetocnotification09/08/2015#joi150096r3