Query the number of files in Windchill

I am looking to update some models using a tool which charges per part, so I need to know how many files I have in my Windchill PDMLink 10.2 database with the file extension ".prt".  So far, we have tried increasing the number of results which will show in our search window to 1,000,000.  Then we simply entered an advanced search for all .prt files.  For some reason we only get 4000 hits but we know we have many more than that.  I was wondering if there is a different way to perform this query in Windchill.