Customers will have bought $966 million in e-books by the end of 2010, according to a new report from Forrester.

The report says the e-book market still has tremendous room to grow, as only 7% of online adults who read books read e-books. Forrester predicts that the e-book market will have risen to almost $3 billion by 2015, even if nothing else changes in the industry, which is unlikely given the rapid development of e-ink technology and the rise of e-book readers in the last couple of years.

The report also highlights a couple of interesting facts about the average e-book reader. She reads the most books, spends the most money on books, and consumes 41% of books in digital form — and that includes people who don't have an e-reader yet.

A recent statement from Amazon, which claims that Kindle books are outselling hardcovers by a large margin, confirms the meteoric rise in e-book popularity. Things are looking equally rosy on the e-reader front, with Amazon claiming the Kindle 3 has been selling better than any previous version in its first four weeks on the market, while Apple said that it sold 4.19 million iPads in its last quarterly earnings report.