WASHINGTON – The nation's high school graduation rate is the highest since 1976, but more than a fifth of students are still failing to get their diploma in four years, the Education Department said in a study released Tuesday.

Officials said the steady rise of students completing their education is a reflection of the struggling economy and a greater competition for new jobs.

"If you drop out of high school, how many good jobs are there out there for you? None. That wasn't true 10 or 15 years ago," Education Secretary Arne Duncan said in an interview with The Associated Press.