comScore: One in ten people over 13 in the U.S. own an iPhone – and that was before iPhone 4S came along

Research firm comScore today released September 2011 mobile subscriber market share data for the United States and the results bode well for Apple’s handset. Of the 234 million Americans age 13 and older, 10.2 percent owned an iPhone during the third quarter, earning Apple the #4 ranking among the nation’s top device manufacturers. It’s the first time the iPhone zoomed past the ten percent milestone in comScore metrics.

Apple between the June and September quarter grew its share by 1.3 percentage points. The achievement is that much more notable because it excludes strong iPhone 4S sales as that handset launched mid-October. In fact, everybody but Apple lost market share, with the exception of Samsung which held on to its 25.3 percent share of U.S. mobile subscribers.

LG came in second with a 20.6 percent share, Motorola was third with a 13.8 percent share, Apple was #4 and RIM came in fifth with a 7.1 percent share. When you consider smartphones only, Apple and Google put together controlled three-quarters of the nation’s mobile platform market share. Talk about the iOS-Android duopoly. Moreover…

During the September quarter, Apple grew by 0.8 percentage points to account for 27.4 percent of the smartphone market in the country, earning them the #2 slot. Google led with a 44.8 percent platform share, up by 4.6 percentage points from the June quarter. RIM was #3 (18.9 percent), followed by Microsoft (5.6 percent) and Symbian (1.8 percent). About 87.4 million people in the country owned smartphones during the September quarter, making the United States the world’s most important market for smartphones. For comparison, IDC estiamted that phone vendors shipped 118.1 million smartphones worldwide during the third quarter of this year.