Federal education officials are handling a record number of disability-related civil rights complaints in the nation’s schools.

In a report out this week, the U.S. Department of Education says that more than 11,700 complaints alleging violations of disability rights were filed with its Office of Civil Rights between 2009 and 2011. That’s the highest number ever received in a three-year period, the agency said.

The vast majority of concerns — more than 4,600 — hinged on the rights of students with disabilities to a free and appropriate public education, or FAPE.

Other commonly cited problems related to retaliation, exclusion/denial of benefits, academic adjustments and disability harassment, the report indicates.

Disability-related complaints accounted for over 55 percent of those received by the Education Department during the three-year period. The nearly 600 staffers in the agency’s Office of Civil Rights also investigate concerns based on race, color, national origin, sex and age.