HOUSTON (AP) — The Texas prison system is facing staffing shortages seven months after designating $9 million to bring down the 14 percent officer vacancy rate.

The Texas Department of Criminal Justice has 3,675 unfilled positions, about 30 more than January when state officials started addressing the issue, the Houston Chronicle reported. Still, prison officials said they're making progress, given the vacancy numbers are down from a peak of 3,930 unfilled jobs in April.

"I am in no way ringing the bell of victory," said Bryan Collier, the department's executive director. "These numbers make me cautiously optimistic."

The system's vacancy rate has long been an issue and stems in part from the facilities' remote locations, tough working conditions and relatively low pay. Officer vacancy rates have been around 13 percent since 2008.

Prison officials this year expanded hiring bonuses of $4,000 and $5,000 to 29 understaffed units and increased starting pay by 12 percent. New guards can now make $36,000 per year instead of $32,000.

The prison system ended up spending over $9.1 million on bonus pay alone, which is more than any fiscal year over the past decade.

The bonuses and pay bumps didn't make much of a difference until May, but figures would be far worse without them, prison officials said.

"Hiring data shows that our recruiting efforts are working and progress is being made shrinking the number of unfilled positions agency-wide," prison spokesman Jeremy Desel said.

Prison officials haven't set an end-date or target goal for the bonuses, according to Desel.

"For the foreseeable future, the bonus pay is in the mix and will be staying because it's working," he said. "It's been an upward trend for the last three months running."

Even with overall figures improving, more units are severely understaffed than last fall when the officer vacancy rate reached 14 percent. Fourteen units were under 75 percent staffed at the end of May.

Huntsville corrections officer Lance Lowry said focusing on new hires only addresses part of the issue.

"A bonus just gets people in the door," he said. "We've never had a problem getting people in the door — the problem is getting those employees to stay."

Lowry suggested mothballing beds at understaffed units instead of closing them entirely.

"There's really only one solution, truthfully," said Scott Henson, policy director of Just Liberty, a criminal justice reform nonprofit. "And that is that we need to reduce the incarceration levels enough to close more units and this time target units with high vacancy rates for closure."