Payroll taxes are imposed by the federal and all state governments. These include Social Security and Medicare taxes imposed on both employers and employees, at a combined rate of 15.3% (13.3% for 2011 and 2012). Social Security tax applies only to the first $132,900 of wages in 2019. There is an additional Medicare tax of 0.9% on wages above $200,000. Employers must withhold income taxes on wages. An unemployment tax and certain other levies apply to employers. Payroll taxes have dramatically increased as a share of federal revenue since the 1950s, while corporate income taxes have fallen as a share of revenue. (Corporate profits have not fallen as a share of GDP).