Cook County Board President Toni Preckwinkle said she is frustrated with the increased number of inmates in county jails.

At a press conference Monday, she said despite efforts to decrease the number of detainees in the jails, the population is actually higher.

She said that about 80 percent of the jail population comes from Chicago, while the city only makes up about half of the county’s population — another reason to continue working with Mayor Rahm Emanuel to curb the city’s ongoing violence problem.

According to Sheriff Tom Dart’s office, in 2011 the number of inmates at Cook County jail was 8,845. In 2012, that number increased to about 9,700.

Preckwinkle said the increase is due to more arrest on drugs and weapon charges.  

And she said once in jail, inmates are also staying longer: In 2007, the average time in jail was 47 days. Now it is 57 days.

“We are studying the data to determine the cause and figure out approaches to population reduction,” she said.

Preckwinkle said she will continue to work with city and county officials on strategies to end crime. One is the new Community Anti-Violence and Restoration Effort (CARE) initiative.

She also announced a $34 million construction project to upgrade and increase energy efficiency in the Cook County Department of Corrections and the Juvenile Temporary Detention Center.

“This critical construction project continues our efforts to modernize Cook County government and promote efficiencies wherever possible, particularly in energy use,” she said.