How has the structure of the personal income tax changed and the share of taxes paid by various income groups changed in recent decades?

Compared to the 1960s and 1970s, the marginal tax rates imposed on those with the highest earnings are now substantially lower. However, even though they now confront lower marginal rates, the share of the personal income tax collected from high income taxpayers is now substantially greater than was true prior to 1980 . Because they are now permitted to keep a larger share of their additional income, those with high incomes now have a greater incentive to earn. As they earn more, the revenue losses from the rate reductions are at least partially offset. At the same time, both the personal exemption and standard deduction have been increased. This helps low income taxpayers substantially, and in many cases, it completely eliminates their tax liability. Thus, compared to the 1960s and 1970s, a larger share of the personal income tax revenue is now collected from those with the highest incomes (for example, the top 1 percent of earners) and a smaller share from the bottom half of earners.