"This study deleted USPS employees. At the same time he is comparing a workforce with an average of a bachelor's degree, and a quarter with a master's degree against the average US workforce ~ hardly a fair comparison."
I would like to see a reference for your profile of the Federal workforce. I seem to recall a lot of A's, C's, and O's in the Federal workforce with which I am familiar. And many of the T's were high school graduates.
Over the last 15 years there's been an incredible demographic change.