About half of the mobile phones used in the U.S., or 49.7%, are smartphones, according to a Nielsen survey.

The finding, based on a Nielsen Mobile Insights survey of thousands of cell-phone users, marks a 38% increase in smartphone usage compared with a year ago, Nielsen said in a blog Thursday.

More than 66% of buyers of a new mobile device chose a smartphone over what's called a feature phone in the three months prior to the February polling, Nielsen added.

Nielsen said Android smartphones make up 48% of the market, while 32.1% are iPhones , and 11.6% are BlackBerries. In the three months ending in February, 48% of buyers chose an Android phone and 43% chose an iPhone, Nielsen said.

Matt Hamblen covers mobile and wireless, smartphones and other handhelds, and wireless networking for Computerworld. Follow Matt on Twitter at @matthamblen or subscribe to Matt's RSS feed . His email address is [email protected] .

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