ICv2 goes to the American LIbrary Association show and reports findings to base:

The two hour “Teen Graphic Novels: Maintaining Your Collection for Maximum Impact!” panel on Saturday was the primary programming event on graphic novels. Teen librarian panelists Brenner, Pawuk, Angela Reynolds (Annapolis Valley, Nova Scotia), and Todd Krueger (Baltimore County), along with moderator Anne Leon (Broward County) spoke to a packed room of 200 librarians, with over a dozen seated on the floor.

The range of sizes and interest in graphic novels on the panels was instructive, with the smallest graphic novel collection (Nova Scotia) only a few hundred books, and the largest (Baltimore) over 16,000 in teen graphic novel volumes alone.

Much more of great interest in the link.