According to emarketer Smartphone Adoption Tips Past 50% in Major Markets Worldwide
More than half of Americans now own a smartphone, according to the latest poll by the Pew Internet and American Life Project.
Nielsen MOBILE MAJORITY: U.S. SMARTPHONE OWNERSHIP TOPS 60%
Canalysis Smart mobile device shipments exceed 300 million in Q1 2013
comScore Reports April 2013 U.S. Smartphone Subscriber Market Share
Asymco Measuring US Mobile Platform Shares: Kantar vs. comScore
Asymco Measuring Platform Churn