47 percent of all tax revenue comes from personal income taxes. Another 34 percents originates with payroll taxes that employers and employees both contribute to. 11 percent of tax revenue comes from corporate income taxes. Those constitute the bulk of federal revenue.
A handful of other taxes and income streams also exist, such as customs duties, excise taxes, and various fees and fines. All these forms of income combined rarely cover 100 percent of government expenditures, however, as this has only happened in 10 percent of the last 50 years. Every other year the United States Treasury borrows the rest.
The current distribution of revenue sources was not always as it appears now. Corporate income tax is approximately a quarter what it was several generations ago. Likewise, excise taxes have fallen to a sixth of what they once were.