Nearly five years ago, New York State's comptroller complained overtime "flows like water" at the Port Authority of New York and New Jersey and called on the bi-state agency to dramatically reign in the extra hours its employees work.

Though the Port Authority has attempted to curb costs, the agency is still struggling to cut overtime, according to public documents.

Nearly 170 Port Authority employees -- mostly police officers and maintenance supervisors - earned more than $75,000 each in overtime last year, according to the agency's payroll. The top 25 on the list each earned more than $110,000 in overtime on top of their regular salaries.

Many employees more than doubled their base salaries by working overtime, the records show. Several took home nearly as much or more than their boss, Port Authority Patrick Foye, who earned $305,111 last year.

Added security for Pope Francis' visit to New York in September, police coverage for construction projects and an unusual number of snow and ice emergency days helped drive up overtime costs in 2015, Port Authority officials said in a report.

"In total, the agency incurred 2 million overtime hours through the fourth quarter. Total overtime expenses were $221 million, which was 17 percent of total labor expenses and $17 million over plan," the report said.

But, Port Authority officials were not too concerned about the extra money.

"After recoveries through flight fees, grants and other reimbursements, and taking into account under-budget straight-time hours at Port Authority Police Department, there was minimal financial impact," the report said.

The Port Authority operates as a joint agency overseen by the New Jersey and New York state governments. Its employees and police force help oversee the region's airports, bridges, tunnels, ports and the World Trade Center site. Its budget is partially funded by bridge and tunnel tolls.

In recent years, the Port Authority has attempted to be more transparent about its finances by publicly tracking its overtime costs and posting its payroll on its website.

The top overtime earner of 2015 was Stephen Olmo, a chief maintenance supervisor in the aviation department who has worked for the Port Authority for 30 years, according to the payroll records.

Olmo earned $186,846 in overtime on top of his $104,814 base pay, the records show. When a longevity bonus, pay for unused time off and other payments were added, his total pay for the year was $325,880.

He was followed by Sgt. Kevin Cottrell, the top overtime earner in the Port Authority Police Department. Cottrell, who has worked for the Port Authority for 24 years, earned $173,706 in overtime on top of his $112,061 base pay.

When his cashed-in comp time, longevity bonus and other pay were added, Cottrell's total pay for the year was $343,335.

Neither Olmo nor Cottrell could be reached for comment.

Cottrell has been cited several times in recent years for helping stop people from jumping off the George Washington Bridge while on duty at the crossing.

The 2011 audit released by New York Comptroller Thomas DiNapoli called on the Port Authority to cut overtime by at least 20 percent and require departments to better justify why they were asking employees to work extra hours.

Port Authority overtime helps drive up public pension costs, DiNapoli said. Because employees at the end of their careers are able to boost their salaries with overtime, their pensions are also inflated.

In its latest overtime report, Port Authority officials listed their plan to help alleviate some of the overtime costs in 2016. The plan includes deploying a new class of Port Authority police graduates to increase the number of available officers and implementing new scheduling software to help better track overtime needs.

Kelly Heyboer may be reached at kheyboer@njadvancemedia.com. Follow her on Twitter @KellyHeyboer. Find NJ.com on Facebook.