According to new IRS statistics, the top 1% of all tax return filers (i.e., those with an AGI of at least $369,691) paid 37.4% of all federal income taxes in 2010, the last year for which the IRS has analyzed data. This is an increase of 1.1% from the previous year.
The top income-earners reported 18.9% of total AGI, also higher than the year before. However, the average tax rate paid by the top 1% fell slightly, to 23.4% of AGI. The top 10% of filers (i.e., those with AGI of at least $116,623) shouldered 70.6% of the total tax burden, while reporting slightly more than 45% of the total AGI.
Access all the data here.