Apple and Samsung Widen Lead in U.S. Phone Market - NYTimes.com

A U.S. smartphone duopoly

"A recent study by the NPD Group, a research company, found that 42 percent of smartphone owners in the United States were using iPhones in the fourth quarter of 2013, up from 35 percent in the same period a year earlier. And 26 percent were using Samsung phones last quarter, up from 22 percent the previous year.
Conversely, fewer American smartphone owners reported having phones made by Motorola Mobility, HTC or BlackBerry, according to NPD.
Nokia, whose smartphones primarily run Microsoft’s Windows operating system, was not even worth mentioning in the study."

Apple and Samsung Widen Lead in U.S. Phone Market - NYTimes.com