Here are the numbers, as of March 31, 2016!

Windows 7
51.89%
Windows 10
14.15%
Windows XP
10.90%
Windows 8.1
9.56%
Mac OS X 10.11
4.05%
Windows 8
2.45%
Mac OS X 10.10
2.06%
Linux
1.78%
Windows Vista
1.41%
Mac OS X 10.9
0.76%
Mac OS X 10.6
0.31%
Mac OS X 10.7
0.27%
Mac OS X 10.8
0.25%
Windows NT
0.07%
Mac OS X 10.5
0.05%
Mac OS X 10.4
0.02%
Windows 2000
0.01%
Mac OS X (no version reported)
0.01%
Windows 98
0.00%

Windows 10 grew 1.33% in March, while 7 dropped .45%. With 7.78% using some version of Mac, Mac is outnumbered by four separate Windows systems. And even Windows 8 (not just 8.1) outnumbers Linux. Windows 98 keeps hanging around the .005% mark-- at least it outnumbers Windows ME.