Enterprise vault report on how many emails are being retrieved (EV Version 11.01)

Hi all - I have been given a task to provide a report on how many emails have been retrieved from EV over a week/month and 3 month intervals.

It's a strange request but i checked through the EV KB's and couldn't find anything.

I don't know if this even possible (on EV 11.01) and I'm guessing it could maybe be done with a auditing or counter on the database.. but any suggestions?

Thanks!