Washington ? One in every 32 adults in the United States was behind bars or on probation or parole by the end of last year, according to a government report Sunday that found a record 6.6 million people in the nation’s correctional system.

The number of adults under supervision by the criminal justice system rose by 147,700, or 2.3 percent, between 2000 and 2001, the Justice Department reported. In 1990, almost 4.4 million adults were incarcerated or being supervised.

“The overall figures suggest that we’ve come to rely on the criminal justice system as a way of responding to social problems in a way that’s unprecedented,” said Marc Mauer, assistant director of the Sentencing Project, an advocacy and research group that favors alternatives to incarceration. “We’re setting a new record every day.”

Nearly 4 million people were on probation, 2.8 percent more than in 2000, while there was a 1 percent increase of those on parole, to 731,147. The number of people in prison grew by 1.1 percent to 1.3 million, the smallest annual increase in nearly three decades. There was a 1.6 percent increase of people in jails, to 631,240. More than half of those on probation 53 percent had been convicted of felonies, according to the Bureau of Justice Statistics report.

Experts noted the recent trend of arrests declined for murder, rape and other violent crimes. Many of those on probation were convicted of using illegal drugs or driving while intoxicated, the report showed.

Whites accounted for 55 percent of those on probation, while blacks made up 31 percent, statistics show. On the other hand, 46 percent of those incarcerated were black and 36 percent were white.