If you create a new report of type "Historical - Interface Traffic" one of the fields available will tell you exactly what you are after. If you go to the "Historical Interface Traffic" item on the field menu you can select either TX, RX or TX+RX and within the relevent submenu there is "Circuit utilization (Max of...)". As long as you have some way of filtering on the correct interfaces, and you can work out some sensible time frames and report groupings you should be on your way.
(I have a report emailed to me every day for our MPLS link utilisation with a time frame of Yesterday and. I then record this info in a big ol' spreadsheet-of-doom for analysis. Can't really share the report as it gets a lot more complex due to working hours, different sources, etc.)