Query to find topics that have not been viewed since X date

Hello!

The goal here is to find content that we can deprecate (hide, or possibly delete) to help us improve search results, among other things. We have about 169,000 topics and many are just not useful anymore as the product we support has changed. One way to determine that a topic can be hidden is to find the topics that simply have not been viewed.

We have the data explorer plugin, but I simply can’t find the field that will tell me the last time a topic was viewed. Am I missing something?