State Department officials are the worst in the federal government for responding as required by law to Freedom of Information Act requests, a new study shows.

The State Department's overall score of 37 percent earned it an "F" on the Center for Effective Government's second annual FOIA report card and put it at the bottom of an analysis of 15 different agencies' handling of records requests.

State's "particularly dismal" treatment of FOIA requests "is completely out of line with any other agency's performance," the center's report said.

While no agency earned an "A" grade this year, the Department of Agriculture and the Social Security Administration got "B" ratings for their FOIA response performance.

The center praised the National Archives and Records Administration for its updated disclosure rules, which made the requesting process easier for people and "encouraged agency staff to release as much information as possible."

But disclosure in the State Department lagged behind all of the other agencies under review.

"The State Department was the only agency in the scorecard whose rules do not require staff to notify requesters when processing is delayed, even though this is mandated by law," the report said.

Although federal law holds all government agencies to the same standards for responding to FOIA requests, some provide records much more slowly and much less completely than others.

The State Department employed 157 full-time staff in 2013 exclusively for the purpose of addressing the public's FOIA requests. According to the analysis, each staff member had to handle 119 cases that year. But the agency still received the lowest processing score of all other federal agencies in the study.

On the other hand, a smaller staff at the Social Security Administration had to process 653 cases each and still managed to put their agency at the top of the list in terms of answering requests rapidly and fully.

The average response time at the Social Security Administration was 18 days, which is less than the 20-day maximum allowed under the law.

Only 8 percent of the State Department's requests were processed within that legal limit, and the average length of time the agency forced requesters to wait for appeals — 540 days — was the longest of any other agency.

Overall, the Center for Effective Government's report showed the majority of the 15 agencies — which together attracted 90 percent of all FOIA requests — improved their handling of records requests over the previous year.

The State Department's approach to FOIA has come under fire in recent days as a result of former Secretary of State Hillary Clinton's use of a private email account and server located in her New York residence throughout her tenure on the job.

Sean Moulton, director of open government policy at the Center for Effective Government, told the Washington Examiner that the heightened attention to the State Department's FOIA program could either slow or speed up the requesting process.

"They have such a backlog and their program for FOIA seems so underdeveloped that an increase in interest is going to be difficult for them to manage," Moulton said. "Now, it's possisible that because of the attention, they'll expedite these materials and any requests for them as sort of a face-saving exercise."

He noted the agency's track record suggests an expedited FOIA process has not been the norm for requests to the State Department.

"If that's the case, then the people bringing their attention to these emails and going through the FOIA process will get a very unrealistic impression of what its like to make a request to State," Moulton said.

The agency's FOIA website, which was overhauled recently to simplify the requesting process, demonstrates the State Department could improve the program if it made the effort, Moulton said.

"They know that this is a problem. The administration knows this is a problem," he said. "On the one hand, I say they have some factors that could be unique to them, but on the other hand, these aren't new problems. They know about these problems."

This story has been updated to include comments by Sean Moulton.