This paper examines the evolution of marginal federal income tax rates from 1980 to 1995. Those rates fell dramatically for most taxpayers. In 1980, three-quarters of taxpayers faced statutory tax rates above 15 percent, but by 1995, less than one-quarter of taxpayers were in that situation. The sharp decreases in rates in 1981 and 1986, which cut top statutory tax rates from 70 percent to 28 percent, were clearly the dominant factor. This is significant because the evolution of marginal tax rates over time is an important barometer of the efficiency of the tax system.