The 12-percent estimate is a milestone for the e-reader. It's the first time that ownership of the device has reached double digits since Pew began measuring e-reader use among U.S. adults in April 2009.

While e-readers and tablets are gaining popularity, both are well below adoption levels of earlier popular consumer tech devices, including cellphones, laptop and desktop PCs, DVRs, and MP3 players.

Mobile phones are far and away the most popular tech device: 83 percent of U.S. adults own one. Desktops and laptops are running neck and neck with 57- and 56-percent, respectively.

The Pew Internet Project findings come from a survey conducted from April 26 to May 22 among 2,277 adults ages 18 and up.

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