Reference: Statistics: IRS Releases FY 2011 Data Book

From the Internal Revenue Service:

The Internal Revenue Service  has released the 2011 IRS Data Book, a snapshot of agency activities for fiscal year 2011 – Oct. 1, 2010, to Sept. 30, 2011. During the year, the IRS collected $2.4 trillion and processed more than 234 million tax returns.
In addition to information on taxes collected and returns processed, the report also includes information about enforcement, taxpayer assistance, and the IRS budget and workforce, among others.
e-File
Taxpayers e-filed more than 133 million business and individual income tax returns, including 77 percent of all individual income tax returns.
Refunds Issued
More than 119 million individual income tax returns, about 83 percent of all individual returns, resulted in refunds, totaling almost $338 billion.
Enforcement
The IRS examined 1.1 percent of all individual income tax returns and 1.5 percent of corporation income tax returns (excluding S corporation returns).
Taxpayer Assistance
The IRS provided taxpayer assistance through 319 million visits to IRS.gov and assisted nearly 83 million taxpayers through its toll-free telephone helpline or at walk-in sites.

Direct to Full Text: 2011 IRS Data Book (84 pages; PDF)
See Also: Past Editions of the IRS Data Book (2000-2010)
See Also: Past Editions of the IRS Data Book (1863-1999)

Filed under: Data Files, Resources