Total Interactions (Events, Calls, Emails, & Tasks) in report for Dashboarding

Total Interactions (Events, Calls, Emails, & Tasks) in report for Dashboarding

Has anyone come up with a way to make this work? It seems like a vital KPI, and I've definitely used it in other CRMs so somebody must have a work-around.

I'm looking for a total across x time period against previous time period.

Thanks,
Andy