http://www.nytimes.com/2015/04/22/upshot/why-workers-without-much-education-are-being-hammered.html?ref=us&_r=0&abt=0002&abg=0
Fascinating article.  "The median earnings of working men aged 30 to 45 without a high school diploma fell 20 percent from 1990 to 2013 when adjusted for inflation."