There's an undeniable fascination with looking at the highest income levels and their tax payments. Adrian Dungan provides a glimpse in "Individual Income Tax Shares, 2014," which was published in the IRS house journal Statistics of Income Bulletin (Spring 2017, pp. 12-23).
Here's a figure showing the share of returns and the share of income taxes paid. For example, the top 1% of income tax returns in 2014 accounted for 20.6% of all income, but 39.5% of all income tax. The top 50% of all tax returns accounted for 88.7% of all income and 97.3% of all income tax. Which in turn implies that the bottom half of all tax returns accounted for 11.3% of all income and 2.7% of all income tax.
A few words of warning are appropriate before over-interpreting the figures here. These figures and percentages apply only to federal income tax. They do not cover the federal payroll taxes that fund Social Security and Medicare, nor do they cover state and local taxes like sales, property, and income taxes. Thus, the figures do not show overall tax burden. The higher burden of income taxes on those with high income levels, as a share of their incomes, can be thought of as counterbalancing how other major taxes like sales tax and payroll taxes weigh more heavily on those with lower incomes, as a share of their incomes.