Most frequent searched QUERY string - Ferret


I need to calculate most frequent searches on a particular model. I am
using ferret for searching in full text mode.

For eg: Search on hospital names. I have a form which allows user to
enter a search query, and underneath ferret does the search and provides
the results.

Now, I would like to show the user, some previous search related data
like Most frequent/popular search data.How can i do that? Does ferret
have any inbuilt mechanism for this or do I have to build my own. Please
suggest on ideas as well.