Can you add more details and a usage case?
I've looked through the existing options, and the only 'by folder' reporting option is 'Top Clients by Total MB Used by Folder' under the Client Session report, but this is an AMP only reporting option that's not available on Master Console.
There currently isn't any report option that does exactly what you're asking for, which means this should be filed as a feature request in the ideas portal on the support site with some additional details (like how you'd like to see the data and the granularity of the data).
As a workaround for now, you can get the data from the folder's client count graph or run individual client session reports on folders locally from the AMP, but this becomes a tedious process with the number of folders you have.