"An estimated 3,745,000 adults were under community supervision at yearend 2021, a 3.5% decline from the 3,881,600 who were supervised in the community on January 1, 2021 (figure 1).1 This decline is attributed to both a reduction in the number of persons on probation, who made up 79% of the community supervision population, and the number on parole. During 2021, the number of persons on probation decreased from 3,032,400 to 2,963,000 (down 2.3%). The number of persons on parole fell from 864,200 to 803,200 (down 7.1%) during 2021, the largest annual change in the population in almost 30 years (not shown)."
Danielle Kaeble. Probation and Parole in the United States, 2021. February 2023. NCJ 305589. Washington, DC: Bureau of Justice Statistics.