E-books were supposed to spell the end of print, but Americans' reading habits have taken a different turn. Here's everything you need to know.

Do most Americans still read books?

Seven out of 10 American adults, or 72 percent, have read a book in the past year — in whole or in part, and in any format — according to a 2015 Pew Research Center survey. That's a steep decline from 1978, when 92 percent of Americans made that same claim, according to Gallup, although book-reading percentages have remained level since 2012. Women and young adults tend to be the biggest bookworms, the Pew survey found. The average woman read 14 books over the past 12 months, while men averaged nine books. Among young adults — ages 18 to 29 — fully 80 percent read a book in the past year, compared with 71 percent of adults ages 30 to 49, 68 percent of those 50 to 64, and 69 percent of those 65 and older.

How are people consuming their books?

They've become hybrid readers, shifting between print, audiobooks, and digital books, depending on the situation. That's a big change from six years ago, when e-books — driven by the launch of the Kindle in 2007, the Nook in 2009, and the iPad in 2010 — exploded in popularity to the point where publishing industry experts were forecasting the death of print books. From 2008 to 2012, publisher revenue just from e-book sales jumped from $61.3 million to $1.54 billion, according to the Association of American Publishers (AAP). E-books accounted for an increasingly large share of the total trade revenue in that same time frame, climbing from 1.2 percent in 2008 to 22.5 percent in 2012. "E-books were this rocket ship going straight up," Len Vlahos, a former executive director of the Book Industry Study Group, told The New York Times. "Just about everybody you talked to thought we were going the way of digital music." Since then, however, e-book sales have largely been flat; in 2015 they totaled $1.37 billion and accounted for not quite 20 percent of total trade revenue.

What happened?

Consumers may be responding in part to the increased cost of e-books. Last year, publishers HarperCollins and Simon & Schuster renegotiated distribution deals with Amazon, winning the right to set the prices of their e-book titles and avoid the discounts Amazon often gave. Now many e-books cost as much as a paperback or even a hardcover. "Since book buyers expect the price of a Kindle e-book to be well under $9, once you get to over $10, consumers start to say, 'Let me think about that,'" Peter Hildick-Smith, CEO of publishing research firm Codex, told The Wall Street Journal. The increased popularity of audiobooks — which can be downloaded through websites and subscription services like iTunes, Audible, and Scribd — also plays a role. Audiobooks accounted for the strongest portion of adult book sales in 2015, bringing in $205.6 million, a 38.9 percent increase from 2014, according to the AAP. The only other sub-section of the adult books category that grew last year was trade paperbacks — boosted by the adult coloring book trend — which climbed 16.2 percent, to $1.4 billion in sales. Sales of all other formats were down, including e-books by 9.5 percent. Another measure of audiobooks' success is publishers' increasing output: The 20 companies that participated in an Audio Publishers Association survey released 35,574 audiobooks in 2015, a 37 percent increase over 2014.

Who is listening to all those books?

Younger readers and fiction fans make up a significant portion of the audience base. Fifty-five million Americans listened to at least one audiobook in 2014, according to an Edison Research survey — and one-third of respondents who characterized themselves as frequent audiobook listeners fell into the 25-to-34 age bracket. Eighty-five percent of respondents said the most important factor in their decision to purchase audio was genre. Mysteries/thrillers/suspense was the most popular listening category, followed closely by history/biography/memoirs and popular fiction.

What are the advantages of audio?

Some people simply prefer listening to text over reading it, but the quality of the performances is a significant factor. Often audiobooks feature talented voice actors or celebrities; Reese Witherspoon, for example, read Harper Lee's Go Set a Watchman; Jake Gyllenhaal recorded The Great Gatsby; and Ian McKellen did The Odyssey. Some audiobook narrators have even developed the followings and star power to drive sales. For example, author Andrew Peterson hired the veteran audiobook narrator Dick Hill — who voices Jack Reacher in the best-selling thriller series by Lee Child — to narrate his debut novel, and it sold four times as much in audio as in other formats. "This is a completely different phenomenon — a cultural and, frankly, aesthetic change in people's habits," Audible CEO Donald Katz told MarketWatch.

Are there other benefits?

Sure. Users can listen to books while working out, doing chores, and commuting (an especially big advantage if you travel by car). The apps that enable listening can be downloaded on your tablet or smartphone, potentially eliminating the need to carry something extra around. If efficiency is your game, audiobooks have set off a trend in "speed listening" — basically, using the variable playback speeds offered by different software to increase the rate at which a narrator is talking. While opting for 1.5 times regular speed is most common, some people set it to as fast as three times the regular speed. But is something lost when listening to a novel narrated in chipmunk-like tones? As podcast host Nate DiMeo told The Boston Globe, "You can listen to Abbey Road [at 45 rpm], but I'm sure George Martin and the Beatles would not appreciate it."