Average full and incremental backup size

Hi Experts,

Can you please advise how can I check average backup size for full and incremental backups for each backup server? Average option can cover for example last 2-3 months. It's a bit difficult for me either because backup starts at 22:00 PM and ends next day. Report Capacity Planning-> Backup->Data-> Data Backuped Up Daily shows amount of data day by day and I have to sum up 2 days manually.

Thank you in advance for any help.