According to comScore (, a “group that measures the digital world,” 74.6 million people in the U.S. owned smartphones during the three months ending in April 2011, up 13% from the three-month period ending in January 2011.

Google Android ranked as the top operating system with 36.4% of U.S. smartphone subscribers, up 5.2 percentage points. Apple also gained share, capturing the #2 position with 26% of the smartphone market. RIM ranked third with 25.7% share, followed by Microsoft (6.7%) and Palm (2.6%).

For the three month average period ending in April, 234 million Americans ages 13 and older used mobile devices. Device manufacturer Samsung ranked as the top original equipment manufacturer with 24.5% of U.S. mobile subscribers, followed by LG with 20.9% share and Motorola with 15.6%tshare. Apple jumped to the #4 position with 8.3% share of mobile subscribers (up 1.3 percentage points), while RIM rounded out the top five with 8.2% share.