The most recent statistics available from the IRS is FY2009. This show that the bottom 50% of all taxpayers, half of the country paid only 2.25% of all of the taxes collected. This consisted of those whose Adjusted Gross Income (AGI) was less than $32,396.
So that means the top 50% of all US taxpayers paid 97.75% of the taxes. These are the people who made more than $32,396 of AGI.
The top 1% of all taxpayers paid 36.73% of the total tax collected. This is everyone who had AGI of $343927 and above.
The chart below shows the percentages and AGI.
Percentiles Ranked by AGI AGI Threshold on Percentiles Percentage of Federal Personal Income Tax Paid
Top 1% $343,927 36.73
Top 5% $154,643 58.66
Top 10% $112,124 70.47
Top 25% $66,193 87.30
Top 50% $32,396 97.75
Bottom 50% <$32,396 2.25
So remember if you make a combined AGI of over $112,124 you are one the wealthiest 10% as far as AGI goes. Congratulations.