The City of Philadelphia doled out nearly $215 million in overtime last year, an increase of $16 million from the previous year and the fourth straight year overtime has climbed, a analysis shows.

A big part of the cause: City officials reduce hiring to control benefit costs. But that also requires massive amounts of overtime to cover the work. Many workers receive more in overtime than their base salaries. That pads retirement benefits and burdens the city's chronically underfunded pension system.

More than 11,600 city employees whose overtime counts toward their pensionable earnings made at least some overtime last year, boosting the workers' annual pay by an average of about $9,000. Police officers and firefighters again earned the largest amounts of overtime, though those earnings do not count toward their pensions.

The most recent total was calculated from the 2014 city payroll.

The 8 percent increase in overtime use last year is potentially troubling in light of its long-term effect on the pension system. Overtime can bolster pension compensation - at times by tens or hundreds of thousands of dollars over the course of a retirement.

In 2014, more than 140 city employees earned more in overtime than they did in base salary, including 75 prison workers, whose overtime pay counts toward their pensionable earnings.

The Police Department gave out $72 million - $6 million more than in 2013 - and again led the city in OT costs. A police spokesman, Lt. John Stanford, said some of the OT cost was due to understaffing.

"The department is slated to have 6,500 sworn [officers] and we currently fall just under that number due to retirements, illness, deaths etc., and also from not having the same amount of new officers to replenish those leaving the department," Stanford said by e-mail. "We would be delighted to add new officers to the ranks."

Other overtime has come from deploying officers to major events like concerts and demonstrations, he said.

The department with the third-largest overtime payments, however, the prison system, reduced its overtime spending by 4.3 percent last year.

City officials monitor overtime trends, mayoral spokesman Mark McDonald said, and work with departments to reduce those costs. McDonald noted that the Fire Department, which had a small bump in overtime payouts last year and, at $37.4 million, is the city's second-biggest OT spender, is implementing unspecified "new measures" to curb overtime.

Four police officers made more than $100,000 in overtime in 2014. Three detectives, John Harkins, Levi Morton, and James Pitts, also broke six figures in 2013.

Topping the list in 2014 was another detective, Donald Marano, who made about $104,000, bringing his total pay to nearly $180,000, according to the payroll data.

The city has said it is trying to curb costs by hiring fewer workers, leading to savings in salaries, health benefits, and other areas, even if that strategy leads to more overtime.

"There are benefits of using overtime," McDonald wrote by e-mail, noting that using OT instead of new employees "does not trigger the array of benefits."