Operating System Market Share in United States Of America - Sep 2018
Windows
36.65%
iOS
28.66%
Android
21.17%
OS X
9.63%
Chrome OS
2.3%
Linux
0.73%

Operating System Market Share in Japan - Sep 2018
Windows
40.15%
iOS
30.25%
OS X
14.33%
Android
11.88%
Unknown
2.78%
Linux
0.4%

http://gs.statcounter.com/os-market-share/all/japan