At least 22% of those who don't pay federal income tax are retirees.

60% work and pay other taxes (including social security and medicare for those deadbeat retirees of the "Greatest Generation&quot .

According to the Washington Post: (if I'm reading it right)

Who doesn’t pay taxes, in eight charts

3) The vast majority of households that don’t pay income taxes are either elderly or paying payroll taxes. As you can see below, 60 percent of those who don’t pay income tax are still working and paying taxes for Social Security and Medicare. Their tax liability is just too low to qualify for the income tax. Another 22 percent of non-payers are retirees.
Only about 7.9 percent of households are not paying any federal taxes at all. That’s usually because they’re either unemployed or on disability or students or are very poor.

Mitt Romney wants to help all Americans struggling in the Obama economy. As the governor has made clear all year, he is concerned about the growing number of people who are dependent on the federal government, including the record number of people who are on food stamps, nearly one in six Americans in poverty, and the 23 million Americans who are struggling to find work. Mitt Romney's plan creates 12 million new jobs in four years, grows the economy and moves Americans off of government dependency and into jobs."

Read more: http://www.businessinsider.com/leaked-47-percent-video-2012-9#ixzz26qPtvOi7