Yes it is true, despite all of the comments to the contrary the wealthy really do pay most of the federal income tax and by a wide margin. The IRS just published their quarterly statistics bulletin Issue Number IR-2009-017. Here is a direct quote from that source:
"Taxpayers filed 138.4 million individual income tax returns for Tax Year 2006, of which 92.7 million (or 67.0 percent) were classified as taxable returns. A taxable return is a one that has total income tax greater than $0. This represents an increase of 2.4 percent in taxable returns from 2005. Adjusted gross income (AGI) on these taxable returns rose 8.5 percent to $7,439 billion for 2006, while total income tax rose 9.5 percent to $1,024 billion. The average tax rate for taxable returns rose, approximately 0.2 percentage points to 13.8 percent for 2006.
Taxpayers with an AGI of at least $388,806, the top 1 percent of taxpayers, accounted for 22.1 percent of AGI for 2006. This represents an increase in income share of 0.9 percentage points from the previous year. These taxpayers accounted for 39.9 percent of the total income tax reported, an increase from 39.4 percent in 2005. The top 5 percent of taxpayers accounted for 36.7 percent of AGI and 60.1 percent of total income tax. To be included in the top 5 percent, a taxpayer must have reported AGI of at least $153,542, whereas, in 2005, the cutoff for this group was $145,283.
This article discusses individual income tax rates and tax shares and the computation of "total income tax" for 2006. It provides explanations of selected terms and describes income tax structure, certain tax law changes, income and tax concepts (the "1979 Income Tax Concept," "modified" taxable income, and marginal tax rates), the computation of "alternative minimum taxable income," and data sources and limitations."
If you focus on the first paragraph, note that only 67% of all of the returns filed during the year even had a tax liability, so fully 33% of those required to file a return did not pay any income tax. Further, many of those persons actually received refunds that were in excess of any amounts they paid in. The actual IRS statistics for 2006 indicate that taxpayrers received refunds via the earned income tax credit of in excess of $39,000,000,000.00. These are refunds to persons in excess of any taxes they had withheld. You can see this statistic at the IRS web page by opening Table 2, here is a link: http://www.irs.gov/taxstats/indtaxstats/article/0,,id=133414,00.html
If you focus on the second paragraph in the above quote from the IRS bulletin you will note that the top 1% of taxpayers accounted for 39.9% of the individual income tax paid for 2006 and the top 5% accounted for over 60% of the income tax paid. This seems like a pretty significant portion to me.
If one chooses to focus on the tax rates associated with the various levels of income, that can be found in Table B of the bulletin. What that table discloses is that persons with adjusted gross income of less than $100,000.00 paid tax at an average rate o 9% while those with adjusted gross income in of more than $1,000,000.00 paid at a rate of 22.6%. So not only is there disparity with respect to the total tax paid, there is also disparity with respect to the rate at which the tax is paid.
As these statistics indicate, the wealthy really do pay most of the federal income tax burden.
You can see the IRS Bulletin at http://www.irs.gov/pub/irs-soi/09winbul.pdf