WASHINGTON - The number of Maryland state prison inmates fell 1.9 percent last year, one of the fastest drops in the nation at a time when state prison populations nationwide were rising overall, according to a new Justice Department report.

A Bureau of Justice Statistics report released Sunday said that there were 23,727 state inmates in Maryland prisons on June 30, down from 24,186 on June 30, 2003. Maryland's rate of decline was the fifth-steepest in the nation, the report said.

"We're working very hard," said Mark Vernarelli, a spokesman for the Department of Public Safety and Correctional Services. He said state officials have tried to keep the population down if possible "and if public safety is served by that."

A spokeswoman for the state Division of Corrections said there was no single program that might have led to the drop. Priscilla Doggett said the state simply took in fewer prisoners than it released during that period.

The Justice Department study did show that Maryland released 10,207 inmates in 2003 and took in 10,170 that year, for example. From 2000 to 2003, the state's prison admissions rate declined by 1.5 percent while releases grew by 2.0 percent, according to the new statistics.

"Although we cannot say that there was any programming factors that contributed to this," Doggett said the department is working on making sure offenders are "more prepared to be productive citizens" when they return to the community after their sentences than they were when they went in.

While Maryland's prison population declined, the number of federal prisoners grew by 5.1 percent between 2003 and 2004, when there were 179,210 inmates. All state prison systems combined saw their populations rise by 1.6 percent in the same period, to 1,315,006, the report said.

Whatever the reason, advocates welcomed the drop in the number of Maryland inmates.

"It's always encouraging when you see the state (prison) population decrease," said Tara Andrews, director of the Maryland Justice Coalition in Baltimore.

But she said it is important to look at what drives the change -- whether it resulted from a concerted effort by the state or if there was a sudden rise in prisoners going on parole.

"We don't have enough information to account for the decrease," Andrews said.

The study said Maryland had the nation's 20th-highest rate of incarceration, with 416 of every 100,000 state residents serving sentences of at least one year at the end of June. That was below the national average of 433 inmates in state prisons per 100,000 residents.