MADISON, Wis. (AP) — A new report shows overtime hours in the state prison system climbed by more than 50 percent as turnover and vacancy rates rose.

State auditors released a report Friday that found the total number of overtime hours within Department of Corrections institutions grew 50.7 percent from fiscal year 2013-14 to fiscal year 2017-18.

The turnover rate for guards grew from 17.8 percent to 26.1 percent during that span. The vacancy rate for all security positions climbed from 6.7 percent to 14 percent.

The adult inmate population grew from 21,941 in 2011 to 23,675 in 2018, a 7.9 percent increase. Operation expenditures for adult corrections rose from an estimated $909.3 million in 2013-14 to $933.9 million in 2017-18, an increase of 2.7 percent.