An article about the subject:
http://www.nytimes.com/2010/08/11/us/politics/11tax.html?_r=1
"But Clockwork," you say, "The New York Times is progressive liberal propaganda!"
Often times yes. So if you feel so inclined, here is the report from the Joint Committee on Taxation, this is a PDF file:
http://www.jct.gov/publications.htm...hk=e4b64755c09042186aa6f272981d99ae&no_html=1