From a discussion of marginal tax rates over at University of Chicago professor John Cochrane's "Grumpy Economist" site:
As a solo general surgeon in private practice, in 2004, with a gross business income before taxes of roughly $500K, I figured that the 39.6% Federal + 9.98% Iowa state top income tax rates + 6% [state] sales + Medicare which no longer peaked out, + property taxes, medical license fees, malpractice fees which were already at $100K for me and headed higher, and no scholarship help for the 4 out of 10 kids in college at the time, my marginal rate was somewhere north of 70%. Once I 'retired' from surgery and became a biology professor, making around $50K, my gross income was one tenth as much, but now one of my kids got a full-ride scholarship at [University], another got a half-ride scholarship, and another got a couple thousand that would not have been given under my earlier circumstances. By my 'going Galt', I figure that the .gov took at least a $200K hit (I remember previously paying $161K in fed. income taxes alone), whereas my disposable income was only about half of what it had been before.