Report most active categories/users?

Is there a plugin that can generate reports on which users or categories produced the most blog posts in a given time period?

I searched the plugin repository for such a tool, but most of what I found were Google Analytics-type services. For the purpose of this report, I’m not interested in pageviews.

This plugin comes close:

http://ww.wp.xz.cn/extend/plugins/graphical-statistics-report/

but it doesn’t let me define the range — it’s only the last 12 months for some reports, and all-time for others.