When President Barack Obama talks about the cost of higher education, his mentions of "college students" might often evoke images of teenagers who spent their senior years of high school searching for the four-year institution that best matched their personalities, then enrolled and moved into the dorms while mom and dad paid the bills.

That idea of a college student spending four luxurious, carefree years studying is passe. Of the more than 20 million students enrolled at thousands of two- and four-year colleges and universities across the nation, only about one-third fit that traditional description.

About 40 percent of all college students are older than 25, according to U.S. Education Department data. More than a third attend classes part time. Nearly 20 percent work full-time. About 60 percent enroll at four-year public and private schools, while the rest mostly attend community colleges or enroll at for-profit colleges. Very few attend the well-known universities topping the U.S. News and World Report rankings.