JOHNSTOWN, Pa. - The state's female prison population has nearly tripled in the last five years, the result of a greater number of drug convictions, officials say.

The population at the state's two prisons that house women - the State Correctional Institution at Cambridge Springs in Erie County and SCI at Muncy in Lycoming County - rose to 1,816 last year. Five years earlier, the prisons housed 680 female inmates, according to the state Department of Corrections.

Female inmates still make up less than 5 percent of the total state prison population, the department said.

Two decades ago, many of the system's female inmates had been convicted of prostitution, said Marilyn Stewart Brooks, the superintendent of SCI-Cambridge Springs. Now, many of the women she encounters are there for convictions for drug-related theft or drug trafficking, Brooks told the Tribune-Democrat of Johnstown for its Sunday edition.

According to the Department of Corrections, 23 percent of the women who served time last year in a state prison were convicted of drug offenses; 16 percent were convicted of murder; and 9 percent were serving time on theft charges.

Brooks also said she had seen an increase in the number of incarcerated mothers and estimated that 70 percent of the female inmates have children.

Because SCI-Cambridge Springs houses inmates from as far away as Philadelphia, the prison has set up teleconferencing sessions between the women and their children.