Finely illustrated and often rich in plotlines, graphic novels have carved out a place on bookstore shelves, just a stone’s throw from Poe, Hemingway and Chaucer. Their popularity has, no doubt, been given a boost by several successful TV shows and movie franchises.

According to Nielsen, unit sales in the graphic novel category are up 10 percent year-over-year in 2013. Although Nielsen does not track actual selling price, the high-priced books at the top of the list are perhaps the most pleasant surprise for graphic novel publishers.

This year, the No. 1 and No. 2 selling books in the category, “The Walking Dead” compendiums by Robert Kirkman, have sold a combined 100,000 copies, and at $59.99 each, the suggested price point is well above that of most soft covers. In fact, “The Walking Dead: Compendium One” is by far the highest-price book on Nielsen BookScan’s bestseller chart for overall adult fiction top 200 year-to-date 2013.

What’s more, Kirkman and his series occupy four of the top five positions on the list of top graphic novels year-to-date. Kirkman’s “The Walking Dead: Compendium One” also saw a 47 percent week-to-week sales lift that coincided with the season finale of the hit AMC series in late March, which drew in almost 16 million viewers.

While Kirkman’s books have sold more than 1,000,000 units over the past 18-months, Naoko Takeuchi—author of the bestselling manga Sailor Moon series—has sold a total of 80,000-copies, and Masashi Kishimoto’s ninja manga series Naruto has sold almost 100,000 copies in 2013.

Of course no Nielsen BookScan graphic novel bestseller list is complete without superhero books like Watchmen, Marvel Avengers, Batman, and The DC Comics Ultimate Character Guide—all of which made the 2013 Top 25.

Top 10 Bestselling Adult Fiction Graphic Novels, First Half 2013