Here is a source that gives tax revenue as a percent of GDP. This includes all forms of tax. Given that the very wealthy increase their wealth primarily through capital gains and not through income and the capital gains tax is quite low it appears reasonable to conclude that the very wealthy are not overtaxed. This isn't exactly how I phrased my statement so I should revise it. I'll revise thusly, taxes in the United States are not high in comparison to historical standards and are certainly not high in comparison to wealthy countries.

http://www.facethefactsusa.org/facts/a-tax-impact-from-grand...