The IRS's Statistics of Income Division yesterday released (IR-2013-26) the Winter 2013 SOI Bulletin (Vol. 32, No. 3), with these articles:

• Individual Income Tax Returns, Preliminary Data, 2011
  (p. 4), by Jessica Holland & Michael Parisi
• Individual Income Tax Rates and Shares, 2010
  (p. 18), by Adrian Dungan & Michael Parisi
• Individual Noncash Charitable Contributions, 2010
  (p. 64), by Pearson Liddell & Janette Wilson
• Split-Interest Trusts, Filing Year 2011
  (p. 92), by Lisa Schreiber Rosenmerkel
• Domestic Private Foundations and Related Excise Taxes, Tax Year 2009 (p. 113),
  by Cynthia Belmonte
• Controlled Foreign Corporations, 2008 (p. 169),
  by Lee Mahony & Randy Miller

Forbes:  New IRS Data: Rich Got Richer, But Paid Lower Tax Rate As Stocks Gained, by Janet Novack:

The IRS today released a new report
showing that in 2010, as the nation’s stock markets recovered, the
richest Americans saw their share of all national income rise and their
effective federal income tax rate fall.

In 2008 and 2009, the wealthy saw their share of national income decline
and their tax rates rise, in large part because their more lightly
taxed capital gains fell.  But in 2010, the top 1% (the 1.35 million
families with adjusted gross income above $369,691), reported  18.87% of
all AGI, up from 17.21% in 2009. Meanwhile their average tax bill (as a
percentage of AGI) fell to 23.39% in 2010, from 24.05% in 2009.

The trends were even more favorable for the top 0.1% (the 135,000
households with income above $1.6 million), who captured the lion’s
share of the 1%’s income gains, garnering 9.24% of all AGI, up from
7.94% in 2009. The tax rate paid by the top 0.1% fell to 22.84% in 2010
from 24.28% in 2009, meaning they paid a lower rate than their less rich
fellow 1 per-centers.   As a result, while the share of all income
taxes paid by the top 0.1% also rose—to  17.88%, from 16.91% in 2010—it
rose by less than the increase in their share of total national income.