The U.S. is running large budget deficits. One reason is that many people don't pay their taxes on time. Often, they don't pay at all. According to a recent report on what the IRS calls the "tax gap," in 2006, only 83% of all tax owed was paid on time. This unpaid tax results from people who don't report their taxes at all, those who don't report all of what they owe, and those who report what they owe but just don't pay it. The tax gap for 2006 was a stunning $450 billion, only $65 billion of which was ultimately recovered by the government. The IRS has produced this overview and a handy tax gap map.