Your contribution to Social Security and Medicare: 15.3% of your salary, up to a limit, half of which is paid by your employer.
A huge number of people pay far more in payroll taxes than they do in income taxes.
On the other hand, the payroll tax isn't a true "tax" in the sense that it isn't supposed to be a source of revenue for the government - it's supposed to be a contribution to an account that you'll be entitled to withdraw benefits from at a later date.
For that reason payroll taxes generally aren't included in discussions about tax cuts:
the only way you can get a cut in your contributions is to (a) accept a corresponding cut in benefits, or (b) have your benefits subsidized by somebody else, or (c) reform the entire system.
See the Social Security and Medicare contributions calculator.