Fox News host Bill O'Reilly falsely suggested that President Obama's proposal to let Bush tax cuts expire could leave some wealthy Americans paying 40 percent of their incomes in federal taxes. But Obama has only proposed letting taxes on the top income bracket increase -- which means only income over $200,000 would be affected -- and very few Americans pay more than 35 percent in U.S. taxes.

This tax discussion comes as the Obama administration and the Republican House try to reach a deal on the automatic tax hikes and spending cuts known as the fiscal cliff.

O'Reilly told guest Adam Corolla that “your state's up to about 14 percent state income tax. President Obama wants to raise it up to about 40 percent federal. That's 54 percent. If he knocks out the deduction for state income taxes, which he wants to do, you'd be paying 54.”

This is a complete misunderstanding of how income tax brackets in the United States work. President Obama has proposed letting the Bush tax cuts for the wealthiest Americans expire, which means the top income tax bracket would increase from its current 36 percent to 39.6 percent. But those rates would only apply to income exceeding $200,000. A taxpayer filing as “single” would currently pay a series of increasing marginal rates on his or her income, beginning with a rate of 10 percent on the first $8700 of income and ending with a rate of 35 percent on income over $388,350. And many taxpayers are able to take deductions, which limit their tax liability.

The taxpayer's effective rate almost always ends up much lower than 35 percent. According to the Tax Policy Center, in 2008, only 10,228 out of 142,450,569 total tax filers paid more than a 35 percent effective tax rate. That's only .0072 percent of tax returns.

As the Center on Budget and Policy Priorities has noted, “a taxpayer's marginal tax rate is the tax rate imposed on his or her last dollar of income.” CBPP added: “Taxpayers' average tax rates are lower -- usually much lower -- than their marginal rates.  People who confuse the two can end up thinking that taxes are much higher than they actually are.”