I imagine there will be a statistical writeup on the sales after it's over. I'm really interested to see the details
There's more info about the average contribution on
http://www.wolfire.com/humble now.
Quite interesting, taking the average contribution for each sale (per platform) results in roughly:
70.9% of sales - Windows (53% Contribution)
16.6% of sales - Mac (24% Contribution)
12.5% of sales - Linux (23% Contribution)
I'm probably out a few percent but that should be broadly correct.
Edit: Clearly I'm a total noob and missed the blog post about this:
http://blog.wolfire.com/2010/05/Linux-users-contribute-twice-as-much-as-Windows-usersFTA:
"Our breakdown for number of donations per platform is: 65% Windows, 21% Mac, and 14% Linux. However, when we look at the amount donated per platform, we see something different. Our breakdown for total donation size per platform is 52% Windows, 25% Mac, and 23% Linux. "