Incarceration in the United States is one of the main forms of punishment and rehabilitation for the commission of felony and other offenses. The United States has the largest prison population in the world, and the highest per-capita incarceration rate. In 2016 in the US, there were 655 people incarcerated per 100,000 population. This is the US incarceration rate for adults or people tried as adults. In 2018 2.2 million Americans have been incarcerated, which means for every 100,000 there are 655 that are currently inmates. This costs the United States government $80 billion dollars a year.