Here's something I read today in this month's Atlantic:

"Many of today’s super-rich started out in the middle and make most of their money through work, not inheritance. Ninety-five years ago, the richest 1 percent of Americans received only 20 percent of their income from paid work; in 2004, that income proportion had tripled, to 60 percent. "

http://www.theatlantic.com/magazine/archive/2011/07/the-14-b...