At the end of June, Amazon’s Kindle family of reading devices was used to read e-books by 55% of e-book buyers, according to figures compiled by Bowker Market Research.

Amazon’s share was up from 45% in the second quarter of 2010 and 48% in the second period of 2011, and the increase was aided by the release of the Kindle Fire. Since its introduction in late 2011, the Fire’s share of e-book reading has risen quickly and hit 18% in June. Some of its gains came at the expense of other Kindle devices, but the combination of dedicated e-readers and tablets gave Amazon its highest market share ever, topping the 49% the company had in the fourth quarter of 2010.

Through its iPad and iPhone devices, Apple had a 15% share of e-reading in June, up from 13% in June 2011 with the gain coming entirely from iPads as the use of e-book reading on iPhones fell by two percentage points in the year-to-year period. Barnes & Noble’s Nook devices had a 14% share in the second quarter, a figure that has held steady since the fourth quarter of 2011, but was down from a peak of 22% in the third quarter of 2010.

As the use of digital devices has steadily grown, far fewer e-book buyers are using computers to read e-books, with the percentage of e-book readers using computers falling to 6% in June 2012, down from 10% in June 2011.

Device Quarter 2 2011 Quarter 3 2011 Quarter 4 2011 Quarter 1 2012 Quarter 2 2012 Desktop/Laptop PC Only 10% 10% 5% 6% 6% Sony Ebook Reader 2 2 1 1 1 Kindle by Amazon 48 47 44 39 37 Kindle Fire 0 0 9 16 18 iPod/iPod Touch/MP3 Device 3 3 2 2 2 Smart Phone 0 0 3 3 3 iPhone 5 4 3 3 3 Nook/NookColor by B&N 15 17 14 14 14 iPad 8 10 9 12 12 Other Device 7 7 8 4 4

Source: Bowker Mmarket Research