<p>I did a really quick Google search, and <a href="http://www.ntu.org/tax-basics/who-pays-income-taxes.html" target="_blank">I found this</a> from a self-proclaimed non-partisan group. 2008 is the most recent year that it has data for.</p>
<p> </p>
<h2 style="text-align:center;"><strong><span style="color:#336699;">Tax Year 2008</span></strong></h2>
<h2 style="text-align:center;"> </h2>
<p> </p>
<table border="1" cellpadding="0" cellspacing="0" style="margin-left:auto;margin-right:auto;"><tbody><tr><td style="width:148px;" valign="top">
<p style="text-align:center;"><strong>Percentiles Ranked by AGI</strong></p>
</td>
<td style="width:148px;" valign="top">
<p style="text-align:center;"><strong>AGI Threshold on Percentiles</strong></p>
</td>
<td style="width:148px;" valign="top">
<p style="text-align:center;"><strong>Percentage of Federal Personal Income Tax Paid</strong></p>
</td>
</tr><tr><td style="width:148px;" valign="top">
<p style="text-align:center;">Top 1%</p>
</td>
<td style="width:148px;" valign="top">
<p style="text-align:center;">$380,354</p>
</td>
<td style="width:148px;" valign="top">
<p style="text-align:center;">38.02</p>
</td>
</tr><tr><td style="width:148px;" valign="top">
<p style="text-align:center;">Top 5%</p>
</td>
<td style="width:148px;" valign="top">
<p style="text-align:center;">$159,619</p>
</td>
<td style="width:148px;" valign="top">
<p style="text-align:center;">58.72</p>
</td>
</tr><tr><td style="width:148px;" valign="top">
<p style="text-align:center;">Top 10%</p>
</td>
<td style="width:148px;" valign="top">
<p style="text-align:center;">$113,799</p>
</td>
<td style="width:148px;" valign="top">
<p style="text-align:center;">69.94</p>
</td>
</tr><tr><td style="width:148px;" valign="top">
<p style="text-align:center;">Top 25%</p>
</td>
<td style="width:148px;" valign="top">
<p style="text-align:center;">$67,280</p>
</td>
<td style="width:148px;" valign="top">
<p style="text-align:center;">86.34</p>
</td>
</tr><tr><td style="width:148px;" valign="top">
<p style="text-align:center;">Top 50%</p>
</td>
<td style="width:148px;" valign="top">
<p style="text-align:center;">$33,048</p>
</td>
<td style="width:148px;" valign="top">
<p style="text-align:center;">97.30</p>
</td>
</tr><tr><td style="width:148px;" valign="top">
<p style="text-align:center;">Bottom 50%</p>
</td>
<td style="width:148px;" valign="top">
<p style="text-align:center;"><$33,048</p>
</td>
<td style="width:148px;" valign="top">
<p style="text-align:center;">2.7</p>
</td>
</tr><tr><td colspan="3" style="width:443px;" valign="top">
<p style="text-align:left;">Note: AGI is Adjusted Gross Income<br>
Source: Internal Revenue Service</p>
</td>
</tr></tbody></table><p> </p>
<p> </p>
<p> </p>
<h2 style="text-align:center;"><strong><span style="color:#336699;">Tax Year 2008</span></strong></h2>
<h2 style="text-align:center;"> </h2>
<p> </p>
<table border="1" cellpadding="0" cellspacing="0" style="margin-left:auto;margin-right:auto;"><tbody><tr><td style="width:148px;" valign="top">
<p style="text-align:center;"><strong>Percentiles Ranked by AGI</strong></p>
</td>
<td style="width:148px;" valign="top">
<p style="text-align:center;"><strong>AGI Threshold on Percentiles</strong></p>
</td>
<td style="width:148px;" valign="top">
<p style="text-align:center;"><strong>Percentage of Federal Personal Income Tax Paid</strong></p>
</td>
</tr><tr><td style="width:148px;" valign="top">
<p style="text-align:center;">Top 1%</p>
</td>
<td style="width:148px;" valign="top">
<p style="text-align:center;">$380,354</p>
</td>
<td style="width:148px;" valign="top">
<p style="text-align:center;">38.02</p>
</td>
</tr><tr><td style="width:148px;" valign="top">
<p style="text-align:center;">Top 5%</p>
</td>
<td style="width:148px;" valign="top">
<p style="text-align:center;">$159,619</p>
</td>
<td style="width:148px;" valign="top">
<p style="text-align:center;">58.72</p>
</td>
</tr><tr><td style="width:148px;" valign="top">
<p style="text-align:center;">Top 10%</p>
</td>
<td style="width:148px;" valign="top">
<p style="text-align:center;">$113,799</p>
</td>
<td style="width:148px;" valign="top">
<p style="text-align:center;">69.94</p>
</td>
</tr><tr><td style="width:148px;" valign="top">
<p style="text-align:center;">Top 25%</p>
</td>
<td style="width:148px;" valign="top">
<p style="text-align:center;">$67,280</p>
</td>
<td style="width:148px;" valign="top">
<p style="text-align:center;">86.34</p>
</td>
</tr><tr><td style="width:148px;" valign="top">
<p style="text-align:center;">Top 50%</p>
</td>
<td style="width:148px;" valign="top">
<p style="text-align:center;">$33,048</p>
</td>
<td style="width:148px;" valign="top">
<p style="text-align:center;">97.30</p>
</td>
</tr><tr><td style="width:148px;" valign="top">
<p style="text-align:center;">Bottom 50%</p>
</td>
<td style="width:148px;" valign="top">
<p style="text-align:center;"><$33,048</p>
</td>
<td style="width:148px;" valign="top">
<p style="text-align:center;">2.7</p>
</td>
</tr><tr><td colspan="3" style="width:443px;" valign="top">
<p style="text-align:left;">Note: AGI is Adjusted Gross Income<br>
Source: Internal Revenue Service</p>
</td>
</tr></tbody></table><p> </p>
<p> </p>