Who pays US income tax?
The US federal government runs off two kinds of taxes: payroll taxes, which fund benefits such as Social Security, and income taxes, which largely fund the rest of the federal budget.
In 2011, the Tax Policy Center studied the tax liability of US households:
53.6% paid income taxes, 46.4% did not
28.3% paid payroll taxes but not income taxes
10.3% were elderly and retired and were not taxed on Social Security benefits
6.9% did not pay any tax with household incomes of less than $20,000 (£12,300)
The majority of those who pay payroll but not income tax do so because of tax benefits for the elderly, families with children and low-income earners