Generate Analytics report on clicks on metatags

We have a central reference library using managed metadata on SharePoint 2010.  Users typically click a Category displayed on a page and get a set of documents tagged with that category.   this is not search.  

We'd like to know which categories are most used. 

But the Audit Log Report generated for the site collection does not provide that data. 

Is there a way to generate usage analytics report based on user clicks on metatags?