Every shop I've ever worked in that has separate Windows and *nix teams has double or triple the ratio in the Windows environments. Windows servers run 90:1 - 120:1, while the *nix boxes run 25:1 - 40:1.
If that is true I would look at the complexity of the applications being served: Windows servers tend to be glorified desktops acting as a fileserver or maybe just a webserver. Hell out of the 50 some odd production Windows boxes we run about 10-20% of them Are domain controllers!! What a waste!
We have probably 6:50 Windows and 2:25 Unix with two who float between the both as needed. If we had to pick a box to lose and never returned I could guarantee you I could list 30 Windows boxes before I got to one Unix box..