Here’s a great bar chart that shows who paid most of the costs of government. It divides Americans into five groups – quintiles – according to their income levels.
The [accompanying] chart … is based on data in the recently-released CBO report “Distribution of Household Income and Federal Taxes, 2008 and 2009,” [PDF] showing the share of federal income taxes paid by income group in 2009. In 2009, almost all (94.1%) federal income taxes collected were paid by just one-fifth of Americans (top quintile) and the top 1% paid almost 39% of all taxes collected. In contrast, the lowest and second quintiles were net “tax collectors” because that 40% of Americans received more in refundable tax credits than they paid in income taxes.”
There are actually six bars. The sixth is informational. It explains that about 39% of the top quintile’s taxes were paid by the top 1% of earners.
Note also that the bottom two quintiles, 40% of Americans, pay less than zero tax.