The plugin:

Statsmeminmum is a plugin for 'Counter-Strike: Source' that runs either via metamod or as a standalone plugin. It tracks players statistics via hitbox detection and saves this in log files. It has accuracy statistics, weapon statistics, hitbox statistics and the obvious kills per death stats. When a player types statsme or rank it gives them a popup menu showing all of their stats. It also shows a menu if you type session, it will output all the data for that session of play into the menu, while showing your overall ranking at the same time. The plugin can also output html files for a website so you can have web statistics with it.

Download and website:

The latest version of the plugin can be downloaded from here. That link has all of the different versions of the plugin, including the standalone version.