Report that shows the average number of interfaces used per device over a week

As part of a project to replace the network infrastructure, Management have asked for a report that shows the Maximum and Average number of used ports on devices over a week.
Similar to the "Ports Currently in use" widget on a node page

I have found an existing report "Current Active Interfaces" which has the same info, but we want to break it down by Group rather than everything in Solarwinds. And then add a Maximum count.


Am I going to have to poke SWQL lots to make this?
Anyone any ideas?