Alabama is making inroads in reducing prison overcrowding, but could see its inmate population balloon in the next five years if state lawmakers don't establish mandatory minimum sentences, a new report cautions.

The report, from the nonprofit Pew Charitable Trusts, praises the state for instituting more work-release programs for nonviolent offenders but stresses the Legislature must enact a binding "truth-in-sentencing" policy.

Currently, judges and prosecutors aren't required to follow voluntary standards enacted by legislators last fall.

Corrections experts see the release of nonviolent offenders through community corrections and time served as crucial to Alabama's ability to control its inmate population, which stands at 28,430.

More than 27,000 inmates are housed in prisons designed to hold about 13,000. About 1,200 are serving their sentences out-of-state because of overcrowding.

Drug offenders, most of whom are considered nonviolent, make up a fifth of the state's prison population. Their number has increased 28 percent since 1999, while the number of violent offenders has increased by 14 percent. The average sentence for drug offenses is nearly 60 percent longer than it was 20 years ago.

Jefferson County's district attorney opposes the voluntary sentencing guidelines, insisting they are too lenient and do more to hurt enforcement than alleviate prison overcrowding.

"It looks to me like the tail is wagging the dog," said David Barber. "The criminals have got to be held accountable. When you start loosening up and backing off, you're sending the wrong message."

If the guidelines were followed, the report's projected 2,000-inmate increase by 2011 would be headed off and the prison population would shrink to about 27,500, according to a state statistician.

"Rather than increasing, the population would stabilize itself," said Bennet Wright of the Alabama Sentencing Commission, an agency created by the Legislature seven years ago.

Sen. Quinton Ross, D-Montgomery, supports work-release programs as well as minimum sentences for nonviolent offenders. The state's "lock 'em up and throw away the key" sentencing mentality comes with a high price tag, he said.

Alabama spends more than $450 million a year on corrections, an increase of 44 percent since 1990. The amount spent on each inmate, however, is only $13,019, the lowest of any state except the $13,009 per offender spent by Louisiana.

"There's not enough money to go around," Ross said. "It's just a situation where you have to do what you can with what you have."

The report, titled "Public Safety, Public Spending: Forecasting America's Prison Population 2007-2011," also points out that Alabama has the nation's highest inmate-to-correction officer ratio -- 6.8 prisoners per staff member.

Corrections Commissioner Richard F. Allen, however, puts the figure even higher. He estimates the ratio at times could be as high as 200 inmates per corrections officer. The state employs 2,600 corrections officers, about 1,300 fewer than a staffing study shows the department needs.

"It raises safety concerns not only for inmates, because they have to be protected from each other, but for our free world staff as well," Allen said.

The Pew Charitable Trusts is projecting that prisons nationwide by 2011 will house more than 1.7 million men and women, up more than 192,000 from last year. That increase could cost taxpayers as much as $27.5 billion more than what they currently spend on corrections.