It's a nice gesture, but I had already bought the first bundle so this is of no use to me..
Judging from the size of the pie chart the mac:linux:win proportions is: 3:3:7. Multiplying these values with the average fee paid by the users yields this result:
The linux part is quite impressive imo.
(granted the proportions are just estimated)
It is possible to select more than one os, did you notice that?