"One in 36 adult Hispanic men, one in 15 black adult men; and one in nine black men ages 20 to 34 are behind bars. While rates of violent crimes has fallen by 25 percent over the last 20 years, prison population has tripled. Overall, the U.S. imprisons more people than any other nation. Second is China, with 1.5 million people in behind bars."
University of Michigan Study