by Cornel Raiu on WordPress.org
Search Analytics for WP will store and display the search terms used on your website. No third-party service is used!

Main statistics view with time filters
Search Analytics for WP will keep history of the search terms used by your users and group them in a set of statistics including the number of posts resulted from that search term.
It can easily aid you in finding what your users are really searching for on your website and make sure you provide exactly what they need.
Help and/or ideas are greatly appreciated! You can contribute to the GitHub repository: Search Analytics for WP
NOTE: Search Analytics for WP stores all the statistics in your WordPress database. No info is sent to third-party services!