College enrollment took a deep dive last year, dropping for the first time since 2006. With figures falling by 467,000, the multiyear growth has officially been stunted, with eyes accusingly turned at the older audience.

New statistics released Tuesday by the U.S. Census Bureau suggest a majority of the decline was due to students 25 years and older, whose enrollment fell by 419,000. Although the Census Bureau did not offer an explanation for the decline, there are a few assumptions to be made.

First? The cost.

The average tuition at a public four-year college has increased by more than 250 percent over the past three decades, leading the average borrower to graduate with more than $26,000 in debt. After the sticker shock sets in, try not to cringe when reminded: that price only promises an undergraduate degree.

Data shows that 22 percent of parents with children under the age of 18 have had to postpone putting money into their children’s college funds, because of their own student loan debt. They could be the same parents striving to obtain a graduate degree, but have shied away in fear of the ensuing, added-on cost.

Federal student loan debt surpassed $1 trillion earlier this year, bringing the country’s total student loan debt, private loans included, to $1.2 trillion.

President Obama addressed the statistic in a recent talk at the University of Buffalo, where he unveiled a new system for rating colleges.

“We can’t price the middle class out of a higher education,” he said. “Higher education cannot be a luxury.”

In an effort to cut costs, colleges will be awarded federal financial aid based on performance as early as 2018. Tuition costs, student loan debt, graduation rates and the average earning of graduates will be factored into the evaluation, among a slew of other measures. Additionally, schools that achieve higher scores will receive larger grants and more affordable student loans.

Obama says he wants the rating system implemented before the start of the 2015 academic year, yet that still doesn’t provide an answer for the debt borrowers are saddled with now. If costs continue to rise, assumptions are that older learners will begin paying more careful attention to emerging online learning platforms.

More than 6.7 million students are now taking classes online, according to a Babson study published early this year. And why not? Harvard and MIT-born massive open online course platform edX added 15 new schools to its system in June, bringing the total number of institutions under the nonprofit’s umbrella to 27. Since launching in April 2012, fellow MOOC Coursera has partnered with more than 60 universities.

Dallas Mavericks owner Mark Cuban is one of many who’s taken a strong stance against the MBA. For “smart students,” he also says the days of one school for four years are over. With learners now being granted the ability to take basics online—say, introduction to physics on Udacity or intermediate algebra on Coursera—why bother forking over the cash for college?

Between 2006 and 2011, college enrollment had grown by 3.2 million, assumedly because of how valuable an undergraduate degree actually is. Yet, this decline, shouldn’t come as a surprise given today’s sky-high costs.

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