Patrick Robrecht

Posts and Users Stats offers statistics about the content and the users of a WordPress installation:
<ul>
<li>Posts per Publication Date</li>
<li>Posts per Taxonomies, i. e. per category, per tag and per custom taxonomies</li>
<li>Posts per Author and Post Type</li>
<li>Posts per Status</li>
<li>Comments per Date</li>
<li>Comments per Author</li>
<li>Comments per Status</li>
<li>Users per Role</li>
<li>Users over Time</li>
</ul>
All statistics are available as a diagram and as a table (which can be exported as CSV).
After the installation you can find the statistics as subpages of Tools.

Posts and Users Stats

Statistics about the number of posts and users, provided as diagrams, tables and csv export.

Posts and Users Stats vs Koko Analytics – Privacy Friendly Statistics for WordPress