They've also been making a bunch of bad decisions, like investing massively into 3D printing which hasn't paid off, and doubling down on Nook again and again.
Coloring books did pay off a little for them, I admit, but at this point it is more a question of "when" B&N will go bankrupt not "if."
Judging by p. 6 of the 2014 10k [1] the number of Regular Stores has fallen from 720 in 2010 to 661 in 2014. Conversely the number of College Stores has grown from 637 to 700, overtaking the number of non-college outlets.
They're still losing money on college stores somehow (baffles me when students are forced to buy multiple $200 textbooks twice a year), but they lose less on their college segment than their regular store segment.
[1] http://www.barnesandnobleinc.com/documents/bn_annual_report_...