The United States has the highest rate of incarceration of any nation on earth: this country contains 4 percent of the planet’s population but 20 percent of its prisoners. This is a relatively recent development. In the early 1970s, our prisons and jails held fewer than 350,000 people; since then, that number has increased to about 2.3 million, with 4.5 million more on probation or parole.
