Among smartphones, Google's Android and Apple's iOS are the leading mobile operating systems in the world. Android's share is estimated at about 60 to 65 percent of the market, while iOS's share varies between 17 to 24 percent. Symbian OS, once a mobile market leader as recently as 2012, has seen its market share drop to less than one percent as of the end of 2015. Mobile OSes are also an important indicator in the smartphone sales market as they reflect sales trends. At one point, Symbian and RIM led the smartphone OS market in terms of sales, representing about 50 percent and 20 percent of smartphones sold at the beginning of 2009, respectively. By the fourth quarter of 2013, Symbian and RIM were installed on less than one percent of mobile phones sold that quarter. Android currently dominates the smartphone market in terms of OS share, being installed on around 81 percent smartphones sold in the fourth quarter of 2015, followed by Apple, with just under 18 percent.
Within the global tablet market, Android and iOS are also leading operating systems there. Apple, a pioneer in the industry, held 95 percent of the market share in the second quarter of 2010. However, with the introduction of a variety of competitive products, Apple iOS's market share dropped dramatically to 24 percent by the beginning of 2015, while Android's share increased steadily. In the first quarter of 2015, almost 70 percent of all tablets shipped worldwide were using Android as their operating system. Despite its decline in market share and increasing competition from companies such as Samsung and Lenovo, Apple still remains the leading tablet vendor.
In regards to desktop PCs, Windows 7 holds the greatest share of the PC operating system market around the world. Windows 8 and Windows 8.1, once intended to succeed Windows 7, have been growing in market share, but have not as yet overtaken their predecessor, and the release of Windows 10 may mean they have missed their chance. Meanwhile, Microsoft's Windows 7 also remains the leader in the computer operating system market, with around 45 percent of the share. Apple's OSX (officially pronounced "Oh Es Ten"), a version of which runs on most of Apple's personal and enterprise computers, corresponded to nine percent of the market share as of December of 2015. The first version of OSX was released in 1999, with the most recent version, "El Capitan", released in September 2015.