A study from the Cleveland Fed finds that income is correlated with progress in high school math. Other studies have shown that the amount of math completed in high school is highly correlated with future educational success.
The causality of the linkage is not known, but it's pretty obvious that a whole raft of higher paying occupations require a significant amount of math. The Fed study apparently looked only at Algebra II, which is pretty low on the math hierarchy, though the other one looked at math up through calculus. Data on higher math doesn't seem to exist, so I guess I will never know whether my evident failure to master algebraic geometry hurt my income.