Back in my lowly days as a shelver at the local public library, we were
expected to shelve 6 shelves (each 36" long) per 3 hour shift.  Number of
books varied but I know my home library which is a mix of mostly
largeformat paperbacks and hardbound, averages 1.1" per book.

Hope that helps,
Brad Coon
Serials Office Manager
Indiana-Purdue University Fort Wayne
 <Coon@IPFW.EDU>