If you take away the elderly (those who have paid into Social Security and Medicare their whole lives and ARE entitled to money from the government), there's only 7% left who don't pay federal tax, and it's because they make under $30,000, not because they're freeloaders.
And the states with the most people not paying income tax? Red states in the South.
And earlier, Romney defined the "Middle Class" as those making $200,000-$250,000. Turns out $200,000 is the top 4.2 percentile bracket.