Hi Matt,
From what I understand its cumulative so all time - in terms of a bespoke configuration, I don't think so (other than when you add new topics you can back-date them for a maximum of 6 months - although it takes mine about a day to update due to volumes).
Potentially 8x8 could 'customise' the view for you but this would come at a cost - best to speak to your Customer Success Manager or Account Manager to see what's possible.
Chris