Income tax in the United States income above £200. The tax proposal was developed in 1814. Because the treaty of Ghent was signed in 1815, ending hostilities and the need for additional revenue, the tax was never imposed in the United States. In order to help pay for its war effort in the American Civil War, Congress imposed its first personal income tax in 1861. It was part of the Revenue Act of 1861 (3% of all incomes over US $800). This tax was repealed and replaced by another income tax in 1862. In 1894, Democrats in Congress passed the Wilson-Gorman tariff, which imposed the first
Income tax in the United States insurance (Social Security) taxes in 2016. The table below also does not reflect changes, effective with 2013 law, which increased the average tax paid by the top 1% to the highest levels since 1979, at an effective rate of 33%, while most other taxpayers have remained near the lowest levels since 1979. Income tax is imposed as a tax rate times taxable income. Taxable income is defined as gross income less allowable deductions. Taxable income as determined for federal tax purposes may be modified for state tax purposes. The Internal Revenue Code states that "gross income means all income from