The Pew Research Center's Internet & American Life Project has released E-Reading Rises as Device Ownership Jumps.
Here's an excerpt:
The percentage of adults who read an e-book in the past year has risen to 28%, up from 23% at the end of 2012. At the same time, about seven in ten Americans reported reading a book in print, up four percentage points after a slight dip in 2012, and 14% of adults listened to an audiobook.
Though e-books are rising in popularity, print remains the foundation of Americans' reading habits. Most people who read e-books also read print books, and just 4% of readers are "e-book only." Audiobook listeners have the most diverse reading habits overall, while fewer print readers consume books in other formats.