Read "The New Jim Crow" by Michelle Alexander. I'd suggest starting with chapter 2 since the introduction as well as the first chapter are more of a manifesto, the data which thoroughly demonstrate the point are in chapters 2-5.

One particularly damning statistic: black people pulled over and searched for drugs are significantly less likely to have drugs than white people.

http://www.nytimes.com/2015/10/25/us/racial-disparity-traffi...

This is a pretty good digest of the figures, but really read The New Jim Crow:

http://www.naacp.org/pages/criminal-justice-fact-sheet