Overall graphic novels sales in the U.S. and Canada for 2008 were $395 million, a 5% increase over 2007 and the slowest rate of growth since 2001, according to the annual report on the market delivered by ICv2 CEO Milton Griepp at the pop culture news site's annual Graphic Novel Conference held at the Javits Center yesterday on the eve of New York Comic-con. And for the first time since ICv2 began tracking the size of this market in 2001, manga sales, the largest segment of the graphic novel market, declined, falling 17%, to $175 million.

Sales of graphic novels in general bookstores continued to grow faster than in comics shops. Bookstores generated $265 million in sales in 2008 compared to about $165 million in sales through the comics shop market (also known as the direct market). Libraries represent about $25 million in sales.

Griepp blamed the decline in manga sales on the tough economy as well as inventory reductions at Borders and the ongoing closing of mall stores. He also cited a decline in exposure of anime on cable TV and the overwhelming popularity of the blockbuster Twilight series, which competed with manga for the consumer dollars of teen girls.