I got frustrated over the overview in time with graphing plugins for redmine. The ones I tried only showed me a growing curve of added tickets, it didnt show any progress or positive feedback. 

I wanted the positive feedback, so I created a quick script which took the atom ticket-list and parsed through it and counted all tickets depending on status:

Just add it to the munin plugin-folder, and it will “just” work. It would be possible to adjust it a bit, so the url comes from the munin plugin config.