“We felt that Books made it clear to readers that our intent is to be inclusive and expansive. These rankings will grow, as we see more of the sorts of migrations you described at the [ICv2 Conference] -- adaptations from other name brand bestselling authors, and so forth. Sci-Fi, Romance, procedurals, and many others, over time.
“We also like the fact that the word Books sets us a bit apart from what might be expected by simply calling them Graphic Novels. The genre has grown even beyond novels. And novel perhaps implies a "novelty," when we might indeed be seeing the evolution of something with a far longer arc, past, present and future. They are an established form, not a novelty likely to recede as a fad. One has only to look at the aisles of any bookstore to monitor their growth."
It's amusing that they insist upon books because "novel" sounds like "novelty." What is a novel, O minds at the paper?
The NYT then divides up the list as follows: Hardcover, Softcover, and Manga (why is Manga separate??). As you can see Naruto just dominates.