What didn’t The Walking Dead own last year? It owned the ratings, especially with young-ish viewers, and some of those fans may have been inspired to check out the original source material, helping to give the comics a boost too.

The Walking Dead started as a comic book series written by the TV show’s executive producer Robert Kirkman, and it’s still going strong today. It actually celebrated its 10th anniversary in 2013, and things are definitely not slowing down in terms of story or sales.

According to Diamond Comics Distributors (via USA Today), Robert Kirkman and artist Charlie Adlard's The Walking Dead No. 115 — part one of the "All Out War" volume — was the best-selling comic of 2013. TWD also had the top comic of of the previous year with its 100th issue. Comic book sales were up overall last year, they added — more than 9 percent over 2012, with single-issue sales up more than 10 percent.

Here's more impressive news: According to Nielsen BookScan, TWD had nine of the top 20 best-selling graphic novels and collections for December 2013, including the top four in a row.

As The Hollywood Reporter noted, "What's particularly impressive in terms of The Walking Dead's success on the chart is the number of times the same material appears on the list. The Walking Dead Compendium Vol. 1 (#1 on the list), The Walking Dead Vol. 1 (#4 on the list) and The Walking Dead Book 1 HC (#10 on the list) all contain the first six issues of the original comic series, in different formats and at different price points — a lesson to publishers to keep material in print and as available as possible, if nothing else."

It sounds like the TV show is still influencing new fans to check out the books. Just in case Robert Kirkman wasn’t rich enough already! Speaking of that guy, he tweeted on January 8, “Hey! The Walking Dead issue 119 is out today! Gotta get 'em all!!” He never stops!

The Walking Dead Season 4 returns with Episode 9 on Sunday, February 9 at 9 p.m. ET on AMC.

Sources: USA Today, The Hollywood Reporter, Comicbook.com