Windows 10's global growth slowed in December, but the operating system ended 2016 on more than a quarter of the world's Windows personal computers.
But in the U.S. Windows 10 continued to gain ground at a consistent clip. By year's end, it powered more than a third of all Windows PCs there.
According to analytics vendor Net Applications, Windows 10 gained six-tenths of a percentage point of user share last month, ending on 24.4% of all personal computers. However, Windows 10 ran 26.6% of all Windows machines: The difference between the user share of all PCs and only those running Windows stems from the fact that Windows powers 92% of all personal computers, not 100%.
User share is an estimate of the proportion of all personal computer users who run a device powered by a specific operating system. Net Applications measures user share by counting devices whose browsers reach websites of its clients.
Although Windows 10's month-over-month growth rate of 2% was only a third that of November, it was still better than the prior two-month stretch, when the OS posted zero or negative growth. That September-October decline, the first ever for Windows 10, came after Microsoft halted a one-year free upgrade offer to consumers and many businesses.
Other metrics sources showed similar results. For instance, Ireland's StatCounter tagged Windows 10's usage share -- a measure of activity rather than of users and their devices -- at 27.2% for November, a 1-point gain that represented a 4% month-over-month increase. Like Net Applications, StatCounter tracked a global growth slow-down in December compared to the month before; in November, Windows 10 posted a 6% month-over-month gain.
But in the U.S., Windows 10's increases persisted.
Windows 10 accounted for more than a third of the visits to sites tracked by the Digital Analytics Program (DAP), which mines traffic to more than 400 domains maintained by U.S. government agencies, such as the Internal Revenue Service and the National Weather Service. The bulk of visits to DAP websites originate in the U.S.
DAP measured Windows 10's share of all Windows at 35.8% for December, up from 34.4% in November. That 1.4-percentage point increase was also the difference between October and November, according to DAP.
The United States has been Windows 10's stronghold since the operating system's mid-2015 launch, with its domestic share of all Windows editions consistently running between a quarter and a third higher than globally. That's not surprising: Home turf has long been a bastion for Microsoft in general, and for Windows specifically, with new versions of the operating system adopted -- and old ones discarded -- faster than the worldwide average.
Even with the free upgrade offer, however, Windows 10 was unable to match the uptake pace of 2009's Windows 7, which last month again accounted for a majority (53%) of all Windows. At the 17-month mark, Windows 10's global user share of 26.6% -- of all Windows editions -- was slightly behind Windows 7's 27% at the same point in its post-launch timeline.