Obtaining list of feature classes in sde that have not been used for over a year

Hi,
I am trying to identify feature classes in sde that have not been used by our internal gis users for over a year. this will help in either moving those layers to a backup server or removing them completely. is there a way to generate a report in either sde or sql server 2008 or any other application or toolset.

Thanks,
Ruchi Basnet