How can you graphically represent the number of authors per page in MediaWiki?

Question

We have a MediaWiki wiki. I'd like to be able to report how much collaboration is going on and I thought of the following graph: number of authors per page. So the data would be like this:

#Pages #Authors
20     1
10     2
25     3

etc. This would show that 20 pages have only 1 author, 10 have 2, 25 have 3, ...

Does anyone know of a way of getting this information?

This information would also somehow need to be shown over time - so if anyone has information on how to do this I'd be grateful. (E.g. last months 25% of pages had 2 or more authors, this month it is 30%).