Returns with Positive Adjusted Gross Income (AGI): Number of Returns, Shares of AGI and Total Income Tax, AGI Floor on Percentiles in Current and Constant Dollars, and Average Tax Rates, by Selected Expanded Descending Cumulative Percentiles of Returns Based on Income Size Using the Definition of AGI for Each Year, Tax Years 2001-2009
IRS, Statistics of Income Division,  July 2011
2012-07-05
<a rel="nofollow" class="external free" href="https://www.irs.gov/pub/irs-soi/09in03etr.xls">https://www.irs.gov/pub/irs-soi/09in03etr.xls</a>