Here are a couple of resources for Linux deployments. The best resource is likely going to be articles.
If you search for "Linux server market share" or "linux servers worldwide" you'll likely find more if you need them.
excerpt from that wikipedia topic
scanning the internet
Server market share can be measured with statistical surveys of
publicly accessible servers, such as web servers, mail servers or
DNS servers on the Internet: the operating system powering such
servers is found by inspecting raw response messages. This method
gives insight only into market share of operating systems that are
publicly accessible on the Internet. There will be differences in the
result depending on how the sample is done and observations weighted.
Usually the surveys are not based on a random sample of all ip
numbers, domain names, hosts or organisations, but on servers found by
some other method. Additionally many domains and ip
numbers may be served by one host and some domains may be served by
several hosts or by one host with several ip numbers.
- W3Techs survey in January 2013 checked the top 1 million Web servers (according to Alexa).
- Security Space survey in August 2009 checked 38,549,333 publicly accessible Web servers.
- Netcraft SSL survey in January 2009 also checked 1,014,301 publicly accessible Web servers, but the survey is only valid for SSL Web servers and it is not a good measure for our purpose.
hardware sales method
A method to measure the overall server market, rather than subsets
like publicly accessible web servers, is to count server hardware
sales, using data from server manufacturers. Using this method, market
share can be measured either in units or in revenue. In either case,
the measure refers to server hardware, not to software. Units refers
to the number of physical servers running a given OS, and revenue
refers to hardware revenue for physical servers running that OS. It
does not refer to software licensing or support revenue, which often
varies considerably from one OS to another.