In the United States, it is annually calculated by the Tax Foundation, a Washington, D.C.-based tax research organization. In the U.S., Tax Freedom Day in 2019 is April 16, for a total average effective tax rate of 29% of the nation's income. The latest that Tax Freedom Day has occurred was May 1 in 2000. In 1900, Tax Freedom Day arrived January 22, for an effective average total tax rate of 5.9 percent of the nation's income. According to the Tax Foundation, the most important factor driving changes in Tax Freedom Day from year to year is growth in incomes, as the progressive structure of the U.S. federal tax system causes taxes as a percentage of income to rise along with inflation.