They're also in lower tax brackets, so their federal tax rate is much lower. Federal income taxes are extremely progressive, and, contrary to popular belief on the left, have become more progressive over the last twenty years or so.
Let's take your example. Someone making $36,000 a year is likely taxed at 15%. Meanwhile, the top tax rate is 35%. That is, folks in the top bracket face federal income tax rates that are 133% higher than someone making $36,000!