get-mailboxfolderstatistics filtering for calendar

We have a policy where we remove items from users calendars after 2 years.  I am trying to figure out the current size of the calendar, and also what the size would be if we only kept 1 year worth of data.

This syntax gets the the size of the calendar in MB:
get-mailbox e144534 -resultsize unlimited | Get-MailboxFolderStatistics -folderscope calendar |  select-object Identity,itemsinfolder,@{Name="FolderSize MB";expression={$_.folderSize.toMB()}} | FT -autosize

How can I add a filter that gives me this data for items less than a year old?

Thanks!

Susan