While doing some work off the info desk, I came across an 2010 Kaplan ASVAB discard. Looking at the catalog I found out that the most stolen/lost/never returned library book type: ASVAB Prep Books.
I only had time to quickly write down stats for the Kaplan series:
2009: 3/9 copies are LOST.
2010: 8/18 copies are LOST.
2011: 10/21 copies are LOST.
I would not be surprised if the rest of the other books in the ASVAB prep series had similar LOST figures. A simple way to fix this problem would be to get rid of all the physical books and only have digital copies. That or require all ASVAB test takers to bring in a written note from their local librarian that their account is in the clear.