Two-thirds of U.S. consumers who purchased a new mobile phone during the second quarter of 2012 opted for a smartphone over a feature phone, according to new data from Nielsen.

Google's Android powered 54.6 percent of all smartphones sold in the U.S. during the second quarter, followed by of Apple's iOS at 34.3 percent. From there, the dropoff is steep: Just 4 percent of new smartphone buyers selected a device running Research In Motion's  BlackBerry, with rival operating systems including Microsoft's Windows Phone fueling the remaining 5 percent of smartphone sales between April 1 and June 30.