How graduating on time pays off

(CNN) -- If you're planning on getting a four-year degree at college, a newly released study suggests you shouldn't take five or six years to get it.

An additional year or two could cost you in more ways than the extra tuition.

The University of Tennessee's Center for Business and Economic Research found that people who earned bachelor's degrees within four years saw, on average, higher wages than those who earned similar degrees within six years.

The difference between the wages of four-year and six-year graduates: about $6,000.

But it still pays to get an undergraduate degree, even if it takes six years to do it. Those who earned a bachelor's within six years made about $6,000 more than students who attended college but didn't earn a degree at all.

The study considered several reasons for the differences in salaries, including the head start that four-year graduates had in the workforce. The authors also noted that some employers may see a difference in aptitude between those who graduate on time and those who don't.

According to U.S. News and World Report, most American college students -- around 60 percent -- don't graduate on time. And an extra year of tuition alone sets them back more than $8,000 at the average public university, while private school (take a deep breath) costs an average of $42,000 per year.

While it's true that many Americans place a priority on getting a college degree, millions of future workers may not need it. A study by the Harvard Graduate School of Education estimates that only a third of new jobs created between 2008 and 2018 will require a bachelor's or higher degree.

Almost as many of those new jobs -- 30 percent -- will require an associate's degree or a "post-secondary occupational credential."

Today's registered nurses, who earn a median salary of over $65,000, may have an associate's degree. Same requirement for dental hygienists, who can earn more than that.

Construction supervisors, electricians and brickmasons, whose education may be acquired through a formal apprenticeship, can earn anywhere from $45,000 to over $60,000.

Still, many businesses won't even interview applicants who don't have college degrees. There's a great deal of pride involved in graduating from a college or university. And for many students, there's a rite of passage in what the college experience provides.

Just keep this in mind if you're setting foot on a college campus this fall: It could turn out that the less time it takes you to graduate, the better.