From May 3, 2010 WSJ:
By JOHN D. MCKINNON
As President Barack Obama pushes to raise income taxes on high earners, opponents are seizing on data that indicates these U.S. households already pay a large and growing share of taxes, even compared with high-tax European countries. And a new congressional study concludes that the percentage of U.S. households owing no federal income tax climbed to 51% for 2009.
Thanks for the link; guess your math is right, then. Wow.