Google’s Android was the only mobile operating system to expand its U.S. market share in the third quarter, according to Thursday figures from Nielsen.

Android increased its market share to 43 percent, up from 39 percent in the second quarter. Apple’s iOS remained flat at 28 percent; Research in Motion’s BlackBerry decreased to 18 percent from 20 percent during the quarter, while Microsoft’s Windows Phone and Windows Mobile platforms slid to 7 percent from 9 percent. Combined in the "other" category, Nokia's Symbian OS and HP's webOS are found in 4 percent of U.S. smartphones.

 

However the Apple iPhone continues its years-long streak as the leading smartphone brand in America, with 28 percent of the market. Nielsen didn't provide a further breakdown among manufacturers, but on Monday, research firm Canalys said HTC had taken the top spot in the U.S. based on shipment estimates alone. HTC shipped around 5.7 million smartphones, followed by Samsung at 4.9 million units. Apple shipped 4.6 million in the third quarter. But don't forget shipment figures can be misleading, as this figure only refers to the number of phones a manufacturer sends to its retail partners and carriers, not the number of devices sold.

Changing at an even faster pace, Nielsen notes, is the rate at which youths and young adults are switching from feature phones to smartphones. Sixty-two percent of U.S. cell phone owners aged 25-34 now own a smartphone, while 54 percent of those aged 18-24 and 35-44 made the switch. Meanwhile, 40 percent of teens aged 12-17 or adults aged 45-54 carry smartphones now.

Lastly, 57 percent of American cell phone owners use feature phones compared to 43 percent of smartphone owners, but that figure is shrinking, Nielsen said.