74% of 25-34 year-olds in the US now own smartphones, according to the latest research from Nielsen. It claims these ‘young adults’ aren’t the fastest adopters of smarter handsets, though. 58% of 13-17 year-olds in the US now own smartphones, up from 36% a year ago. “Among most age groups smartphones represent the majority of U.S. mobile subscribers, but American teens were the age group adopting smartphones the fastest,” says Nielsen’s Nichole Henderson, who thinks mobile operators and handset makers should be thinking hard about how to market to teens. Meanwhile, Nielsen has tracked all age groups’ purchases of smartphones in the last three months, finding 58.6% chose Android, 33% iPhone and just 2.7% BlackBerry, with other platforms accounting for 5.8%.