During 2007, Tax Foundation economists estimate that roughly 46.6 million tax returns faced a zero or negative tax liability. These are the so-called non-payers, people whose exemptions, deductions and credits wiped out any tax that would have been due. As a result, every dollar that was withheld from their paychecks during the year was refunded. In about half the cases, substantial additional money was "refunded" to the tax filer, although that portion is classified as a government expenditure since it is actually welfare spending, not a tax refund.
Almost a third of all tax returns, 32.6 percent of 143 million federal tax returns filed, were nonpaying in 2007, the most recent year for which IRS data is final. The percentage for 2007 is the second highest, a slight tick down from the all-time highest in 2006, when 33.0 percent of tax filers paid nothing.