Surprisingly, Windows XP's marketshare rose from 11.99 percent to 12.23 percent. Despite no longer receiving security updates since April 8, 2014, quite a number of people are still counting on XP.
Apple's OS X accounted for 9.09 percent in February, pretty much the same as January's 9.10 percent. Windows Vista's marketshare dropped from 2.69 percent to 2.53 percent while all Linux distros combined saw their total marketshare rise from 1.46 percent to 1.55 percent.
Here we have the current marketshare:
And here's an overview of the trend:
There's also a chart that shows operating marketshare per country. The marketshare of each OS varies greatly from country to country but Eritrea seems to be the only country in the world where Windows 7 isn't the most widely used operating system.