The current version of Archive manager does not support this yet, however, in advanced search you can get the number of archived emails that are older than 10 years but it does not count the size of it. Please refer on the link below.
Also, there are two possible ways for calculating the size of a user mailbox regardless of age of email.
Statistics (Archive Size) which helps you to report the size of the mailbox after archiving
Archive size report create reports containing the status of user mailboxes to get an overview of the entire size of mailboxes in the HSM store including message size, archived size, archived size uncompressed, shortcut size and the limit of mailboxes as well.
Message Size - total volume of emails archived, size before archiving, counted from Exchange
Archive Size - total volume of emails archived, size after archived, sitting in HSM, compressed if configured
Uncompressed - archive size in uncompressed state + metadata
Shortcut size - total volume represented by stubs, sitting on Exchange side
For more details, please refer to the KB article Below.
