Android (operating system) top-selling platform in April 2011, overtaking BlackBerry OS with a 31.2% smartphone share, according to "comScore". By the third quarter of 2011, Gartner estimated that more than half (52.5%) of the smartphone sales belonged to Android. By the third quarter of 2012 Android had a 75% share of the global smartphone market according to the research firm IDC. In July 2011, Google said that 550,000 Android devices were being activated every day, up from 400,000 per day in May, and more than 100 million devices had been activated<ref name="i/o 2011 stats"></ref> with 4.4% growth per week. In September 2012, 500
Usage share of operating systems down to 72.76% and Chrome OS at 3.33%, plus traditional Linux at 1.46%. There is little openly published information on the device shipments of desktop and laptop computers. Gartner publishes estimates, but the way the estimates are calculated is not openly published. Another source of market share of various operating systems is StatCounter basing its estimate on web use (although this may not be very accurate). Also, sales may overstate usage. Most computers are sold with a pre-installed operating system (OS); some users replace that OS with a different one due to personal preference, or install another OS alongside it