In 2009, just 50.5 per cent of Americans paid any income tax to the federal government - the lowest proportion in at least half a century.
And the number of people outside the tax system could have climbed even higher since as the economic downturn has continued to bite and unemployment has remained high.
The decreasing number of taxpayers threatens government revenues, and could also cause resentment from those who believe that welfare recipients are taking money out of the economy.
151.7million U.S. citizens paid no federal income tax in 2009, according to figures compiled by the Heritage Foundation, a right-wing think tank.
In 1984, the middle of the Reagan era, 85 per cent of Americans paid federal income tax, meaning just 34.8million people did not. “