The number of people reading e-books is growing by leaps and bounds. Just before Christmas, 2011, 17% of American adults said they had read an e-book. By mid-February, 2012, that number had jumped to 21%.

Pew Research Center’s Internet & American Life Project surveyed almost 3000 people age 16 and over about their e-book reading experiences.

They found not only that e-book readership is growing, but also that e-book readers tend to read more books. Over the past 12 months, e-book readers averaged reading 24 e-books over the last 12 months. Print book readers averaged 15 books per year.

They also found that the number of people reading e-books at any given moment has increased nearly four-fold. According to their report, 45% of book readers read a book, in one format or another, on any given day. In June of 2010, when asked whether they had read a print book or an e-book ‘yesterday,’ 95% said ‘print,’ and only 4% answered ‘e-book.’ By December of 2011, that had changed to 84% saying ‘print,’ and 15% saying ‘e-book.’

In a head-to-head competition, Pew Internet’s survey found that more people prefer e-books over print books when they are traveling, when they want to get a book quickly, or when they want a wide variety of books to choose from. But e-books did not win the head-to-head battle across the board. When it comes to reading to children, 81% of those surveyed preferred print books. 69% preferred print books when sharing books with others.

With the popularity of e-books growing, why would anyone not want an e-book reader? There were several reasons that people gave for not owning one. On the top of the list was that they just don’t want one or need one. Additional reasons were that they can’t afford one, already have enough digital devices, and/or that they preferred printed books.