As of February 2012, almost half of U.S. mobile subscribers now own smartphones, according to Nielsen. That marks an increase of 38 percent over last year, when only 36 percent of mobile subscribers owned smartphones in February.

Nielsen says that overall, Android continues to lead the smartphone market in the United States, with 48 percent of smartphone owners saying they owned an Android OS device. Nearly a third of smartphone owners have an Apple iPhone. BlackBerry owners represented another 11.6 percent of the smartphone market.

Among recent acquirers who got their smartphone within the last three months, 48 percent of those surveyed by Nielsen in February said they chose an Android and 43 percent bought an iPhone.