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:
mac 24.388
linux 38.108
win 44.45
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?