by AJ Plus @ajplus. The United States incarcerates more people than any other country in the world. With 2.2 million people behind bars and millions more on probation or parole, 1 in 35 American adults is caught up in the prison system.y AJ Plus @ajplus. The United States incarcerates more people than any other country in the world. With 2.2 million people behind bars and millions more on probation or parole, 1 in 35 American adults is caught up in the prison system.