© Creative Commons image via flickr user agrilifetoday
The Internal Revenue Service and the Tax Policy Center in Washington have some statistics that will likely make last-minute filers extra-irate today: The super-rich are paying less in income tax than they used to, and nearly half of all U.S. households don't pay any income taxes at all.

The IRS tracks the 400 highest adjusted gross incomes, and how much they pay in income taxes, each year, reports the Associated Press. In 2007, the last available year for IRS data, the average income in that set was around $345 million, and they paid about 17 percent in federal income taxes. In 1992, the average income tax rate for the same set was 26 percent.

Think tank Tax Policy Center also has data that show that about 45 percent of households receive so many tax breaks that they won't pay federal income tax at all for 2010. The tax code contains $1.1 trillion in credits, deductions and exemptions, around $8,000 per taxpayer.

"It's the fact that we are using the tax code both to collect revenue, which is its primary purpose, and to deliver these spending benefits that we run into the situation where so many people are paying no taxes," Roberton Williams, a senior fellow at the Tax Policy Center, told the AP.