The share of adults in the United States who own an eReader doubled in May 2011 to 12 percent from 6 percent in November 2010, according to the Pew Internet Project. Tablets haven’t seen the same level of growth in recent months. In May 2011, 8 percent of adults report owning a tablet, up only 1 percent since and 3 percent since November 2010.

These findings come from a survey conducted from April 26-May 22 among 2,277 adults ages 18 and over, including surveys in English and Spanish on landlines and cell phones.

The study found that both eReader and tablet adoption levels among U.S. adults are still far below the adoption of other tech devices. According to the study, cell phones are the most popular digital device among U.S. adults today, followed by desktop and laptop computers, DVRs, and MP3 players.

Interestingly, the study found that there is overlap in eReader and tablet ownership, as 3 percent of US adults own both devices. In addition, nine percent own an eReader but not a tablet, while 5 percent own a tablet but not an eReader.