A new study has found that Americans’ use of e-readers to read their books is on the rise. Over a fifth – 21% – of Americans have now read at least one e-book, and their popularity is growing, especially among avid readers.

The Pew Internet survey polled 2,986 Americans aged 16 and up between November 16th and December 21st 2011. Follow-up surveys were conducted January 5th-8th and January 20th-February 19th in order to gauge the impact of the 2011 holiday season on the use of e-readers. The survey found that e-books are most popular among avid readers, and that e-book readers use a variety of devices to read their books, including tablets, smartphones, and dedicated e-readers like the e-ink Nook and Kindle.

The survey also found that the 2011 holiday season had a significant impact on the use of e-readers. During the initial survey, only 17% of respondents said that they had read an e-book in the last year, compared to 21% after the holiday season. E-readers were apparently major Christmas gifts, as ownership of e-ink readers (like the Nook and the Kindle) jumped 9% from December to January. Ownership of tablets – including the iPad and the Kindle Fire – also jumped 9%, from 10% to 19% of respondents in both cases.

Interestingly, e-book readers read more books in all formats than those who don’t read e-books. The average respondent who said they read e-books had read 24 books in any format in the past twelve months. Those who didn’t read e-books had read an average of 15 books during the same timeframe.

There was no difference between tablet owners and owners of other e-reading devices in terms of the number of books read, but there were other differences. Women, whites, the well-educated, and those over 65 all reported reading more books in the past year than men, minorities, the less well-educated, and under 65 age groups.

Interestingly, the use of e-readers appears to be a driving force in the increase of reading in general. Forty-one percent of tablet owners said they spend more time reading thanks to the increasing availability of e-content, while 35% of e-reader owners said the same. Overall, 42% of e-book readers say they read more than they used to. What’s more, this trend increases the longer you own an e-reading device (tablet or e-reader): 41% of those who have owned such a device for at least twelve months read more than they did before, while 35% of those who have owned their device for six months of fewer say the same. This is especially true of men under the age of 50.

Even so, print books are not (yet) in danger of being overtaken by e-books as the preferred method of reading. Those who read e-books said that they prefer e-books for ease of access and portability, but when reading to children and sharing books with friends they still preferred printed books. The study also found, though, that 45% of people who are reading a book on a given day are reading an e-book. What’s more, they’re doing it on a variety of devices. Of those who read e-books, 41% said they use a dedicated e-reader like a Nook or Kindle, while 23% do so on a tablet like an iPad, Nook Tablet, or Kindle Fire. Also, 29% read on their smartphones (Amazon, Barnes & Noble, Apple, and Google all have apps that allow e-books to be read on smartphones as well as tablets). Perhaps most surprisingly, 42% of respondents said that they read e-books on their computer.

The survey also found some unfortunate news for libraries: the majority of book readers of all kinds preferred to buy their books rather than borrow them. Readers of e-books were more likely to feel this way: as 61% said they preferred to buy rather than borrow, while 54% of those who don’t read e-books preferred to buy. Conversely, only about a third (32%) of those who listen to audiobooks preferred to buy rather than borrow. The fact that audiobooks are usually considerably more expensive than their print or digital counterparts is likely a major factor in that.

The full study can be found here.

How do you read? Do you use an e-reader? A tablet? A smartphone? Or do you prefer printed books? Will e-books ever replace printed books? Let us know what you think in the comments.