There are great differences among states. What I know is that the income in the developed areas in the northeast and west of the United States is relatively high.

Take a small rural area in the south where I live as an example.

Doctoral student: 1600 USD a month (before tax)

Posting Doc 2500-3000 (before tax)

An associate professor or assistant professor earns $40,000-$70,000 a year (before tax).

Professor, that may not be true.

If you have a position, then the income depends on how you do it, and the students are fixed.