LINCOLN, Neb. — Nebraska’s corrections director said Friday he is optimistic the state’s prisons will become less crowded even though a series of reforms haven’t yet reduced the inmate population as expected.

Scott Frakes told a legislative committee that the prison system has custody of 5,306 inmates, a decrease of 77 since he became director in February 2015.

Nebraska’s prison population grew 20 percent between fiscal years 2003 and 2013, prompting lawmakers to approve an overhaul package that expanded treatment programs. The corrections department has faced a barrage of problems over the last two years, including a riot that left two inmates dead, an increase in staff assaults and the escape of two convicted sex offenders.

Frakes acknowledged that the current inmate population fails to meet projections made by the Council of State Governments Justice Center, a nonprofit group that made recommendations to lawmakers designing the overhaul. The group had predicted the system, which was designed to house up to 3,275 inmates, would have 4,800 by now.

The decrease “is not enough, but it’s a positive trend,” Frakes said. “It’s important to recognize that (the department) is just one piece of the larger criminal justice system.”

Frakes said the department has taken longer than expected to implement some changes approved by lawmakers and Gov. Pete Ricketts, such as the use of a risk-needs assessment tool. The tool helps determine which inmates are most likely to reoffend and who needs the most treatment.

In addition, Frakes said the department is still struggling to provide adequate programming for sex offenders, violent inmates and those suffering from addictions. Some inmates drop out because they don’t like the programming and others are removed for behavioral problems, he said.

But Frakes said he expects the situation to improve by next year, and expressed confidence that the department can still meet its goal of being just 40 percent over its design capacity by 2020. He pointed to an effort to add 160 beds at the Community Corrections Center in Lincoln, which is ahead of schedule.

In June, Nebraska’s inmate population was 58 percent higher than what the prison system was to designed to hold, according to the Department of Correctional Services.

Prison officials are also struggling to hire new employees, said Diane Sabatka-Rine, the department’s deputy director of operations. The department has requested a $15.6 million budget increase to hire new employees and is negotiating with the prison workers’ union, but “when we don’t have applicants coming in the door, it’s hard to hire people,” Sabatka-Rine said.

Some lawmakers say the crowding and staffing shortages have contributed to a rise in inmate assaults on prison employees.

Staffers reported 141 assaults between Jan. 1 and the end of August, including 10 which resulted in serious injuries. Last year, staff members said they were assaulted 143 times, with five incidents that led to serious injury.

“That’s an alarming trend,” said Steve Lathrop, an attorney for the committee and former state lawmaker who led previous prison investigations.