That's the latest word from research firm , which reports that Android's lead in the U.S. smartphone market continues its steady rise. In fact, nearly 52 percent of U.S. smartphone owners use Android devices. Second-place iOS has a healthy 34.3 percent of the market.

Third-place RIM has just 8.1 percent, and other operating systems take the final 5.9 percent of the pie.

Obviously, the Nielsen numbers are very good news for Android and iOS. And the gulf between the two frontrunners and the rest of the mobile OS appears to be widening.

Among smartphone owners who purchased a handset in June 2012, 54.6 percent chose an Android device, and 36.2 percent bought an iPhone.

Meanwhile, Microsoft's Windows Phone platform continues to languish. That's despite positive reviews, a slick "" interface, abundant advertising, and support from major phone manufacturers including Nokia, HTC, and Samsung.