This statistic below shows the mobile OS (operating systems) market share in the United States from January 2012 to June 2017. In June 2017, 53.3% of U.S. smartphone subscribers were using a Google Android device. Apple was the second most popular mobile OS with a market share of 44.9%. Android’s closest competitor in the US smartphone operating system market is Apple’s iOS, which held a market share of 43 percent in December 2016. source