By Karen Holt

E-book sales grew exponentially in the first quarter of 2010, jumping from just 1.5% of total US book sales in 2009 to 5% of the market in the first quarter of 2010, said Kelly Gallagher, vice president of publishing services at R.R. Bowker, who presented the findings of Book Industry Study Group (BISG) research Wednesday during BookExpo America.

The BISG’s “Survey of Consumer Attitudes Toward E-Book Reading” consists of three surveys taken over the course of nine months. The most recent findings and their implications for the industry include:

Thirty-seven percent of e-book buyers bought their first digital book within the last six months. Because so many consumers are only beginning to develop the habit of buying e-books, publishers have an opportunity to shape expectations about such things as pricing and the timing of digital releases.

Among e-book buyers, 25 percent said they bought fewer print books than before. Fifteen percent said they buy no print books, and 9 percent said they wouldn’t buy a print book even if the title they wanted wasn’t available digitally. This shift means publishers will be forced to reduce print runs, resulting in higher per-copy costs.

E-book purchases have been increasing among higher-income consumers, but not among those who are less affluent. To continue growing the market, publishers must find a way to make e-books accessible to those with lower incomes.

Asked what they would do if the e-book version of their favorite author’s title was not available at the same time as the hardcover, 32 percent said they would wait to buy the ebook, and 21 percent said they’d buy the hardcover.

When asked whether DRM would affect their decision to buy an e-book, 31 percent said yes, and 39 percent said maybe — an indication that publishers need to carefully weigh the trade-off between protecting their content and keeping their customers happy.