Why is my database growing so much?

I really haven’t been posting or adding all that much content to my blog, but in the last 3 weeks, my database went from 19MB to 25MB. From 3/18 to 5/25/2012, it has gone from 9MB (version 3.3.1 then) to 25MB (3.3.2 now). I did install a few plugins at the beginning of this period, and I’m wondering if one of them is adding to the database on a daily basis or something. How do I find out which part of the database is growing, and maybe, use that to pin-point which plugin is adding the data?