I love the plugin. I needed something like this to measure the count of my postings per month and to calculate the average. I looked at wordpress.org and found your plugin. It fits. :-)
But there a little bug.
The columns in the charts are linked to the corresponding monthly archives. The link has the following format:
But long ago, I changed the permalink-format to:
So the page with monthly archives is located under:
If the plugin would analyse the permalink-format, it should be possible to generate the correct links.