By Hannah Johnson

The Kindle and other e-reading devices have gotten lots of news coverage recently as retailers continue to drop the price of devices in order to gain a larger share of the growing e-book market. The Kindle is now priced at $189 (down from $259), and both the Kobo Reader from Borders and the Nook from Barnes & Noble are available for $149 (originally the Nook was $259).

But the e-reader market is going to get even bigger, says Amazon. In a press release on Monday, Jeff Bezos, CEO and founder of Amazon.com, said: “We’ve reached a tipping point with the new price of Kindle — the growth rate of Kindle device unit sales has tripled since we lowered the price from $259 to $189”.

But even more interesting is the news that “Amazon.com customers now purchase more Kindle books than hardcover books”.

In the past three months, Amazon sold 143 Kindle books for every 100 hardcover books. In the past one month, they report selling 180 Kindle books for every 100 hardcover books. Amazon’s total e-book sales in the first six months of 2010 have tripled over the first half of 2009.

While the iPad was called a “Kindle Killer” when it first came out, the Kindle seems to be surviving quite well. Kindle applications for iPhone, iPad and Android might also be a factor of its success, because customers are not tied to a single reading device if they buy a Kindle book. If Amazon decides to drop the Kindle price even further in the future, that could give it an edge over the $499 iPad with price-conscious consumers.

As for hardcover sales, Amazon said it sees continued growth in that segment. The Association of American Publishers also reported that as of May 2010, hardcover sales for the year-to-date were up 21.7%. Despite that, publishers have voiced concerns in the past that Amazon’s competitive e-book pricing could cannibalize their hardcover sales.

The good news is that the readers are still out there, still hungry for more books, and still willing to spend money on electronic content.