With the release of Windows 8.1 to the world in October, Microsoft ended 2013 with two full months of availability for its latest operating system version. While Windows 8.1 is certainly growing quickly and eating into Windows 8′s share, the duo has only now been able to pass 10 percent market share, while Windows 7 seems to be plowing forward unaffected.

The latest market share data from Net Applications shows that Windows 8 and Windows 8.1 made steady progression in December 2013, gaining a combined 1.19 percentage points (from 9.30 percent to 10.49 percent). More specifically, Windows 8 gained 0.23 percentage points (from 6.66 percent to 6.89 percent), while Windows 8.1 jumped 0.96 percentage points (from 2.64 percent to 3.60 percent).

Meanwhile, Windows 7 gained 0.88 percentage points (from 46.64 percent to 47.52 percent). Unlike in November, Windows 7 didn’t gain more share in December than Windows 8 and Windows 8.1 combined, but it is still growing.

os market share december 2013 Windows 8 and Windows 8.1 pass 10% market share, Windows XP falls below 30% (Updated)

Windows 8, which saw its biggest gain in August at 2.01 percentage points and its biggest loss in November at 0.87 percentage points, may not have lost share last month, but it will likely continue to slip overall. All Windows users are being encouraged to get the latest and greatest, and Microsoft is making the upgrade path to Windows 8.1 just a free download away for Windows 8 users.

Going back to earlier versions, Windows Vista gained 0.04 percentage points (from 3.57 percent to 3.61 percent). Yet the biggest mover was Windows XP: it dropped a huge 2.24 percentage points (from 31.22 percent to 28.98 percent). We didn’t think it would fall below the 30 percent mark before 2014 was over, and yet here we are.

In 2013, Windows lost share every month except for March, July, and November. In December, Windows slipped 0.15 percentage points (from 90.88 percent to 90.73 percent). OS X dipped 0.02 percentage points (to 7.54 percent), while Linux gained 0.17 percentage points (to 1.73 percent).

Net Applications uses data captured from 160 million unique visitors each month by monitoring some 40,000 websites for its clients. StatCounter is another popular service for watching market share moves; the company looks at 15 billion page views. To us, it makes more sense to keep track of users than of page views, but if you prefer the latter, the corresponding data is available here (Windows 8 is at 7.57 percent).

Update: Net Applications tweaked its numbers for December a few hours after its original report was released, and this article has been adjusted accordingly.

See also – IE11 more than triples market share to 10.42%, Firefox slips a bit, and Chrome gains back share

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