A new report from Nielsen shows that as of February 2012, just about half of US mobile subscribers own smartphones (49.7 percent) — an increase of 38 percent over last year, when only 36 percent of mobile subscribers used them. Perhaps more importantly, Nielsen says that smartphones have momentum in the market, with consumers opting for them over feature phones by more than two-to-one — a similar figure to the one Nielsen reported back in January. We've already known that over half of 18 to 44-year-olds had a smartphone as of late last year, but this newest report demonstrates that smartphones are on their way to general market dominance. Nielsen reports that Android smartphones lead the pack with 48 percent of smartphone owners saying they own an Android OS device, followed by the iPhone at 32 percent, and BlackBerry at 12 percent. For new buyers, Nielsen says the spread is a bit different, with 48 percent opting for Android, 43 percent for the iPhone, and just 5 percent for BlackBerry.