Final answer:
The prison population reached its highest level in 2007. The incarceration rate in the United States has grown considerably over the years, but it has started to decline in the past decade.
Step-by-step explanation:
The prison population reached its highest level in the year 2007.
The incarceration rate in the United States has grown considerably in the past hundred years, but it has started to decline in the last decade. In 2007, the total correctional population, including those on parole and probation, peaked at 7.3 million, with approximately 1 in 32 people being under some form of correctional supervision. Since then, the numbers have decreased, with the 2018 correctional system figure being close to 6.4 million people.
Sources:
Justice Policy Institute Report: The Punishing Decade, & U.S. Bureau of Justice Statistics Bulletin NCJ 219416 - Prisoners in 2006