Source: Aviva Aron-Dine, Center on Budget and Policy Priorities, March 29, 2007

In a new study, Thomas Piketty and Emmanuel Saez, economists who have done groundbreaking work on the historical evolution of income inequality in the United States, examine how the progressivity of the federal tax system has changed over time. Unlike previous analyses, theirs examines effective federal tax rates going back to 1960, including income, payroll, corporate, and estate taxes, and provides data for income groups reaching up to the top one-hundredth of one percent (.01 percent) of the population. Several crucial findings emerge from their study.