On average, 15.1 percent of all U.S. postsecondary students who received undergraduate degrees in 2010-11 had previously attended college in at least one other state or territory.
Student Mobility – 2012 (PDF)
On average, 15.1 percent of all U.S. postsecondary students who received undergraduate degrees in 2010-11 had previously attended college in at least one other state or territory.