Half of American adults own a smartphone or tablet computer and most of them use these devices to access news, a study found. The finding has major implications for how news will be consumed and paid for, a survey of news use on mobile devices by the Pew Research Center\'s Project for Excellence in Journalism said. The recent growth in mobile numbers is the rapid acceptance by Americans of the tablet computer, with 22 percent of U.S. adults -- almost double the number from a year earlier -- now regularly using a tablet, a Pew release issued Monday said. Sixty-four percent of tablet owners and 62 percent of smartphone owners say they use the devices for news at least weekly, the survey found. Users are not just checking headlines on their devices, the survey found: Many also are reading longer news stories, with 73 percent of adults who view news on their tablet saying they read in-depth articles at least sometimes, while 19 percent said they do so daily. The numbers are similar among smartphone users, Pew said. \"The evidence is also mounting that mobile devices are adding to, rather than replacing, how much news people consume,\" Project for Excellence in Journalism Deputy Director Amy Mitchell said. \"Even with the broadening population and wide range of competing activities, mobile owners are drawn to news on their tablet and smartphones.\"