At a Capitol Hill gathering to honor the 35th anniversary of the Individuals with Disabilities Education Act, Education Secretary Arne Duncan said more needs to be done to ensure the law’s promise.

Hailing IDEA as “a major civil rights victory” Duncan told a group of educators, policymakers and advocates Thursday that much progress has been seen, noting that 95 percent of students with disabilities now attend neighborhood schools and almost 60 percent of special education students receive regular high school diplomas.

However, he acknowledged that 35 years after Congress mandated a free and appropriate education for children with disabilities, “we have a long way to keep the promises of IDEA.”

“Through IDEA, we learned that students with disabilities will succeed if challenged and given support to reach higher standards,” Duncan said. “We all know that we aren’t yet providing a world-class education for every child with a disability. And we won’t rest until we do that.”

The law now known as IDEA was originally enacted on Nov. 29, 1975 as the Education for All Handicapped Children Act. At that time, nearly 1.8 million kids with disabilities were excluded from public schools.

Also on Thursday, the House of Representatives approved a resolution honoring the IDEA anniversary.