New data from the National Student Clearinghouse Research Center show that 37.2 percent of college students transfer at least once within six years. The research is based on the center's virtually comprehensive database of American college students. It tracked first-time students who enrolled in college in 2008.

Students often cross state lines (which means they don't necessarily show up in state databases of students or graduates). The clearinghouse said nearly a quarter of transfers from four-year institutions left the state. And community college was the top destination for transfer students from four-year institutions, with 53.7 moving to a two-year community college.