It might actually not be that bad - from wikipedia's page on the company that produced that statistic: http://en.wikipedia.org/wiki/Net_Applications
[quote:18id7dn2]Criticism
While the statistics released by the company routinely place Operating Systems sold by Microsoft (Windows) and Apple (Mac OS X) with a high market share in the desktop computer category (through 2013), Vincent Vizzaccaro (EVP - Marketing and Strategic Alliances, Net Applications, 2002-) has stated that Microsoft and Apple are among the company's clients.[2] The company has also admitted that their statistics are skewed.[3] These admissions and the fact the company doesn't make their data sources or processing methods public, has led many to criticize the company (e.g.[4]); questioning their impartiality and the reliability of their statistics.
Checking other sources, steam claims about 10.55% of their users are on those systems, and another source for web browsing stats claims about 16.8%.
That's still a large percentage though...