Over the past year, the number of people who read an e-book has jumped a lot, especially among twenty-somethings.
Interestingly, as you can see in this chart from Pew Research Center, the twenty-somethings lagged behind their 30-49-year-old counterparts, who had read more e-books the year before and maintained a steady appetite for them this past year. The jump this past year seems to have mostly affected people in their twenties and fifties, which suggests it may be related to technology adoption — both groups tend to have less spending money for consumer electronics.
Also, the number of e-books each group read doesn't seem to have affected how many books people read overall. According to Pew:
The typical American read five books in 2013, according to the Pew Research Center's new report on reading and e-readers. That's the median, rather than the average, meaning half of Americans read more than five books and half read fewer; if you look just at people who read at least one book last year, the figure rises to seven. All those numbers are similar to findings from previous years. (We focused on median rather than average readership because a relatively small number of very avid readers skews the averages higher — to 12 books for all adults and 16 for adult readers.)
"Reading" encompassed printed books and e-books as well as audiobooks. Overall, print remains the dominant way Americans read books: More than two-thirds (69%) of people said they had read at least one printed book in the past year, versus 28% who said they'd read an e-book and 14% who said they had listened to an audiobook. 87% of e-book readers and 84% of audiobook listeners also read a print book in the past 12 months.
Read more at Pew Research Center