SOUNDBITE (English) Professor Frances Hill, tax law expert, University of Miami Law School:"It is true that 47% of Americans do not file a federal tax return, and we should reasonably then say, why? Well, of those people, of that 47%, approximately 22% of them are very elderly and no longer have to file. And most of the rest of them are working poor who don't make enough to file federal income taxes. But those who are working are paying payroll taxes at a rate of over 15%. And because they don't make very much, that would mean their entire wage would be taxed at that level. It's worth noting that 15% exceeds the tax rate that candidate Romney has admitted to paying on the great deal of investment income that he has, which was about 13.9%"We have a thousand or two thousand very wealthy people who are not paying any income tax either, because of various provisions of the Internal Revenue Code." "The decision to exempt people with very low incomes, generally under 20,000 dollars, was enacted by Congress beginning with President Reagan's tax bill in 1986, which was bipartisan. And then enhanced dramatically, by President George W. Bush in 2001 and 2003 which took a lot of people off the tax roles as a price of cutting the tax rate of upper-income individuals so dramatically. (****END****) ANCHOR VOICE: -------------------------VIDEO PRODUCER: matt friedman---------------------------VIDEO SOURCE: ap-----------------------VIDEO APPROVAL: ----------------------------VIDEO RESTRICTIONS: none