Query Last Run Date

We are attempting to remove queries no longer in use and are using the delivered query run time stats record (PSQRYSTATS) to obtain info on last run date.  However, we have found that the stats do not include queries included and running from a group build definition.  Is there somewhere we need to turn on stats in order to capture those queries?  Are there any other scenarios where a query may be executed, but not captured in PSQRYSTATS?  Thank you.