Well, maybe I put that wrong. Maybe the disparity is because blacks work less, and thus get less income. Look here. Be sure to look at the months worked and then look at the monthly income. Notice that out of 4 months, whites work an average of 2.6 months while blacks work 2.3 months. That’s a difference of about 9 days.
Education. There are more whites with degrees than blacks with degrees. Furthermore, there is a higher percentage of white people who get degrees than of blacks. So, for example, if 9 out of ten degree holders were white, and 1 out of ten were black, then whites would get more of the higher paying jobs and thus there would be an income disparity.
Sidenote: Asian Americans actually make more than whites in many cases. Obviously, being a minority has nothing to do with getting a good job.