The levels of security in a prison system are categorized differently around the world, but tend to follow a distinct pattern. Most developed countries divide prisons into separate security classes depending on the inmate population and the security needed to keep them under control. Accordingly, most developed countries have classes ranging from the most secure, which typically hold violent prisoners and those judged most likely to escape, to the least, which are most often used to house non-violent offenders or those for whom more stringent security is deemed unnecessary. Below are prison statistic to show how out of control the prison population has become, explaining the current state of the U.S. criminal justice system.