In SharePoint 2013 Document Library there is a option in ribbon "Most Popular Items" when i click, its show me zero count.
Is there any data in the Web Analytics reports for your site collection? (Go here) http://Yoursite.com/sites/_layouts/15/Reporting.aspx?Category=AnalyticsSiteCollection
If all of those are empty there may be an issue with Web Analytics in your SharePoint farm. Then you might want to look at this troubleshooting guide:
In my case i get count from database (WSS_UsageApplication), by running query from "proc_GetSlowestPages" procedure.