The Federal Budget: Discovering Data The accompanying graph shows the highest bracket of individual income tax rates in the U.S. tax system over the past 100 years. FRED Highest rate: Percent 100 90 80 70 60 50 40 30 20 10 0 - 1920 U.S Individual Income Tax: Tax Rates for Regular Tax: Highest Bracket 1940 1960 . When the income tax was first introduced, what was the rate on the highest bracket? % 1980 Source: U.S. Department of the Treasury. Internal Revenue Service 2000