Jacquelyn Martin / AP Photo Prospective students tour Georgetown University's campus in Washington, Wednesday, July 10, 2013.

College enrollment in 2012 declined by nearly a half million students compared to a year earlier, according to new figures released by the U.S. Census Bureau, with students over the age of 25 leading the miniature exodus from higher learning.

Enrollment at colleges and universities among students aged 25 and older dropped by 419,000 last year, while enrollment among younger students dropped at about a tenth of that rate, according to the statistics released Tuesday.

The drop-off comes amid an overall increase in college enrollment, with 3.2 million new students entering classrooms between 2006 and 2011, according to the Census Bureau.

Among the groups that bucked the trend in the past year were Hispanics, who saw enrollment rise by nearly 450,000 between 2011 and 2012, which constitutes an increase from 11 percent of the college student population to 17 percent. The percentage of black students also ticked up slightly, to about 15 percent.

"This increase in the number of Hispanics enrolled in college can be attributed to the combination of an increase in the adult Hispanic population and their climbing likelihood of being enrolled," Census Bureau statistician Julie Siebens said in a release.

A total of 10.3 million people were enrolled in four-year colleges in 2012, according to the new Census Bureau numbers. Another 3.8 million were enrolled in graduate schools, and nearly 6 million were enrolled in two-year colleges.

The Census Bureau report, titled School Enrollment: 2012, is the latest in a series of studies that seem to show that older people who fled to colleges and universities during tough economic times might be headed back into the workforce.

Enrollments at all institutions were down about 2 percent for the spring of 2013, according to a study from the National Student Clearinghouse Research Center.

The dip in older students could be due to an improving economy, as the age group has otherwise seen a steady increase in enrollment between 2000 and 2011, according to figures from the Department of Education.

President Barack Obama took a two-day tour in late August to campaign for college affordability, stopping at locations in New York and Pennsylvania. Among other initiatives, Obama pushed for a college rating system that would help students and their parents determine which colleges would provide the best return for their tuition dollars.

"We've got a crisis in terms of college affordability and student debt," Obama said during a stop at the State University of New York at Buffalo. "We can't price the middle class, and everybody working to get into the middle class, out of an education."

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