Market data from Net Application indicates Microsoft's Windows operating system lost 0.3 percent marketshare in December 2009. It was the eight month in 2009 during which Windows lost share, the operating system ended the year with a marketshare of 92.2 percent, compared to 93.66 percent in January 2009.
Although rival desktop operating systems -- Mac and Linux -- essentially remained flat, mobile OSes, including Google's Android and Apple's iPhone OS, took up the slack created by Windows' dip. Mobile operating systems, said Net Applications, now power 1.3% of all the hardware that surfs the Internet.
Windows finished the year with a 92.2% share, down 0.3 of a percentage point. It was the eighth month in 2009 during which Windows lost share.
As it did in 2008, Windows' decline again accelerated in the second half of the year, when it lost 1.2 points of share. That compared to a drop of just 0.5 of a percentage point in the first six months of 2009. In 2008, Windows also lost more than twice as much share between July and December as it did in the preceding six months.