Have you ever wondered which comic books CGC has graded the most often? As collectors, it's important to know the answer to this question since it may provide insight into both supply (how many graded books are available for purchase) and demand (which issues collectors deem important enough to grade). Let's dive into this question by analyzing the Top 10 CGC submissions of all-time.

And a big "thank you" to Greg Holland for providing the data below through his website, CGCData.com!

Five of the top ten CGC submissions of all-time are related to Spider-Man's alien costume saga.

We all know that Spider-Man is the most famous Marvel superhero of all-time so it's probably no surprise that your friendly neighborhood Spider-Man dominates this list of CGC submissions. But what is interesting is that Spider-Man's relationship with the alien symbiote is clearly a favorite among serious collectors. In fact, all five of the Spider-Man related key issues among the top 10 are related to the symbiote.

With nearly 37,000 submissions to CGC, No. 1 on this list is Amazing Spider-Man #300. The popularity of ASM #300 among collectors is the result of a perfect storm; it has an iconic cover drawn by one of the most famous artists of all-time (Todd McFarlane) who was at the top of his game; it contains the origin and first appearance of one of Spider-Man's most famous villains (Venom); and is the 300th issue in one of most important comic book series of all-time (perhaps only after Action Comics and Detective Comics). As a side note, the popularity of Todd McFarlane cannot be underestimated; Spawn #1, a book written and drawn by McFarlane, ranks No. 2.

The other symbiote-related comics in the Top 10 include: Amazing Spider-Man #361 (first full appearance of Carnage) at No. 3; Marvel Super Heroes Secret Wars #8 (origin of the symbiote) at No. 4; Amazing Spider-Man #252 (ties for first appearance of the symbiote) at No. 8; and Venom: Lethal Protector #1 at No. 9.

Four of the top ten CGC submissions of all-time are related to mutants.

Not surprisingly, just behind Spider-Man are mostly mutant-related key issues. Coming in at No. 5 is New Mutants #98 which contains the first appearance of Deadpool with just under 30,000 submissions to CGC. Wolverine, in Wolverine Limited Series #1, appears for the first time on this list at No. 6 with over 28,000 submissions. Notably, Wolverine Limited Series #1 is the only Bronze Age book to appear in the Top 10. The only issue from the Uncanny X-Men series, Uncanny X-Men #266 (second appearance of Gambit), occupies the No. 7 position. And finally, X-Men #1, the best selling comic book of all-time, rounds out the Top 10 with over 20,000 submissions.

Every issue in the Top 10 were published during the period of 1982-1993.

This also isn't a surprise, but the majority of the books that appear in the Top 10 are either late Copper Age or Modern Age books. The immense popularity of Todd McFarlane and Jim Lee in the late 1980s led to the "comic boom" of the 1990s. In an attempt to meet demand, Marvel published millions of comic books in the 1990s, flooded the market, and suppressed the value of most comics published during this time period. There were also plenty of comics lying around in high-grade that could be submitted to CGC.

One last observation is that there isn't a single DC comic in the Top 10 on this list. In fact, a DC comic doesn't even crack the list until No. 37: Batman: The Killing Joke. I was surprised to see that Batman: The Dark Knight Returns #1 barely made the Top 100 (it's No. 91).

Were you surprised by any of the comics that were (or weren't) among the Top 10 CGC submissions of all-time? Please let us know what your thoughts are in the comments section below!