E-books aren't just becoming increasingly popular. They also appear to be promoting reading habits among American adults.

So says new research from the Pew Internet and American Life Project, which states that about one-fifth of U.S. adults have read an e-book in the past year.

And if you expand that to include Americans over 16 who have used an e-reader device or app to read news articles or magazine-style features, the figure jumps to 43%.

E-book users tend to read more often than people who read only print material, Pew found. In particular, they read more books. A typical e-book user read 24 books in the past year, compared with the 15 books reported by typical non-e-book users.

Also, a third of people who read e-content say they now spend more time reading than they did before e-books. This is especially true for people who own tablets and e-book readers.