How often do students change their major?

I read that 80% of students change their major at least once, and that most students change 3 times. I have yet to find a reliable source, so if anybody could provide me with a link, I would really appreciate it. Thank you.How often do students change their major?
I changed mine 3 times myself. Most students do NOT know what they want when they go to college...they just think they know...only to find out, they hate it or cannot do well in it or they find out its not for them, so they change it. Most undergraduates EXPLORE through the first two years or so, sometimes 3. By your junior year, you should have an idea of what it is you really want to do.