Lol
Actually it would be hard to tell, really, because on 1and1 there's no way to check how much data transfer occured by domain name basis, like with page views and unique visits. Before Omni opened, I used about 25-30 GB a month through most of 2008, then 35 GB. Then it slowly went to 40-45 during a few months, late 2009-early 2010, then in March 65-70 GB. Now we hit about 75 I think. You need to keep in mind that a lot of mp3 files are hosted on this webspace, as well as some videos and computer games, so that takes a considerable amount of bandwidth compared to small calc programs.
Fortunately this package has 1200 gigabytes of monthly bandwidth, so we're not even close to exceeding it.
On a side note, on the server, Omnimaga is about 2-3 GB large, while TIMGUL is 9-10 GB large (about 1600 song files, a lot of which are unfortunately corrupted, though)