The United States' problem with mass incarceration and private prisons cannot be overstated. The US has 5% of the world’s population and 25% of its inmates. The US’s incarceration rate is the highest in the world, in fact more than 4 times the world’s average.
The US has 2.2 million people serving time in prisons and jails, and more than twice that many on probation or parole. Since 1980 this population has more than quadrupled. Private prisons enjoyed a re-birth in the U.S. that began in approximately 1980.