The IRS has released Fiscal Year 2013 Enforcement statistics. In FY 2013, IRS Enforcement collected more revenue than FY 2012, with fewer employees and while examining fewer returns than in FY 2012. Collection activities, such as levies, liens and seizures all dropped significantly. However, criminal investigations and prosecutions have risen.
The IRS statistics can be found here: http://www.irs.gov/PUP/newsroom/FY%202013%20Enforcement%20and%20Service%20Results%20–%20WEB.pdf