Exporting built in reports

I have a client on version 3.9 that would like to be able to export the bestsellers built in report to Excel.  Is this something that could be added or accomplished somehow in my current version?  I'm sure I could get it out of the database with a sql script but it's something they would like to be able to run themselves like they can with the orders export.

It would require customization.  You can search the marketplace for 'report'

We have written the export as a plugin for version 4.4 & 4.5 if that helps at all, you can find it here https://plugins.3xsoftware.co.uk/export-reports-for-nopcommerce