The US has a 'flat tax' when all combined taxes (federal, state, local) are accounted for.
Chapter 7, Page 93-94
"The tax burden on the top 1 percent is nowhere near that high (43% of all taxes), although so many politicians and antitax advocates have made such false claims so many times that millions of Americans believe it to be true. The top 1 percent paid 36 percent of the income taxes in 2001. But when the burden of all federal taxes is added up--corporate profits, estate, gift, Social Security, Medicare and excise taxes--they only paid 25 percent."...
"For 2001 the government found that all taxes at all levels of government consumed 19 percent of incomes of the best-off fifth of American, those individuals and families whose average income was $116,666 that year. Down at the bottom the poorest fifth, whose average income was $7, 946, paid 18 percent.
What this means is that the entire tax system at all levels amounts to a flat tax, one that is crushing the poor and the one that does not extract the harsh levies so often cited by politicians who owe their allegiance to the political donor class."
BTW, if you want to read the most incendiary books, or give them as Christmas gifts to your freeper inlaws for instance, I can think of Perfectly Legal along with Kevin Phillip's book Wealth and Democracy. There will be much freeper 'weeping and gnashing of teeth' after they read those two !
In Perfectly Legal, Johnston goes on to explain the federal Bureau of Labor Statistics annual consumer expenditure survey ( see
http://www.bls.gov/news.release/cesan.toc.htm for more information and research and also the wikipedia site
http://en.wikipedia.org/wiki/Consumer_Expenditure_Survey )
You can check the "Personal taxes" at
ftp://ftp.bls.gov/pub/special.requests/ce/aggregate/2005/higherincome.txt
scroll to the bottom of the page