I don't know what industry you are in...
The italian subsidiary of IBM.
...but MS is *far* from being dominant in the server space it's not even close.
UNIX-oids are by far the most used overall except for niche markets that are by definition tied to Windows like .NET etc.
Among the 10000+ servers I can have access to, here: 850 use Linux (mainly SUSE, Red Hat and a few others), about 2600 use another UNIX dialect (counting Solaris, MVS, AS/400 and others), about 650 are physical VMware hosts (ESX/ESXi, any version), and all the rest are Windows machines. Which means 70% of servers hosted here are Windows (and not unixes) machines. You may argue that all over the world the situation may be different, but I can assure you it's a good sample of the whole server universe. Little industries that can't afford hosting in the farms of a great IT company and prefer keeping their machines in-house generally choose Microsoft too, because it offer robust integrated solutions for the web (IIS), for email (Exchange), and there's a pletora of 3rd party products that can work aside or together with them, with the relative ease of use of Windows. The myth of the server world using 99% Linux has never been true and it's extremely far from the actual situation.