here's my proof:
http://www.washingtonpost.com/blogs/...d0iK_blog.html
When you add up all of the various taxes, and look at the effective tax rates, it is clear the tax system is already pretty progressive. Everyone pays some tax, even those who pay no federal income taxes, and the wealthiest pay a larger percentage share of taxes. Here?s the effective tax rate for all of the groups, according to the CBO:
Lowest quintile (23.4 million taxpayers), zero to $18,900: 4.3 percent
Second lowest quintile (22.4 million), $18,900-$32,100: 10.2 percent
Middle quintile (22.9 million), $32,100-$47,400: 14.2 percent
Fourth quintile (23 million), $47,400-$71,200: 17.6 percent
Highest quintile (23.6 million), above $71,200: 25.8 percent
Top 10 percent (12 million), minimum income of $98,100: 27.5 percent
Top 5 percent (5.9 million), minimum income of $134,400: 29 percent
Top 1 percent (1.1 million), minimum income of $332,300: 31.2 percent