According to the IRS, for 2007:
The top 50% of taxpayers paid 97.1% of income taxes
Top 25% paid 86.6%
Top 10% paid 72.2%
Top 5% paid 60.4%
Top 1% paid 50.4%

Oh, we tax income in this country, not wealth. If we taxed wealth, there probably wouldn't be much.