October 2015 was a strong month due mainly on the strength of Marvel sales. Not only did Marvel take all ten slots in for the first time since January 2005, it took 18 of the top 20. The unit sales for Marvel within the top 300 was the highest it has ever been, at 4,174,721, topping the previous high point in December 2008 by a little over 20,000 units. DC, on the other hand, sold 1,975,093 units within the top 300 comics -- below its average of 2,353,258 during the final order era, which began in March 2003.

RELATED: SALES CHARTS: Iron Man, Spider-Man, Spider-Gwen & More Lead Marvel to Massive October Sales

Marvel accounted for 52.67% of the total unit sales of the top 300 comics, DC for 24.92%, and all of the other publishers combined for the remaining 22.4%. This is the highest percentage of the top 300 comics unit sales Marvel has had since December 2009, when it hit 52.62%. The highest percentage of the unit sales for the top 300 Marvel ever had was 55.57% in June 2009 with 3,648,665 units. It is worth noting that Marvel's highest percentage of the top 300 unit sales was obtained with 526,056 fewer units than Marvel sold in October 2015. This clearly illustrates the percentage breakdown of the top 300 comics unit sales and the overall market breakdown are useful metrics only within a given month. Comparing those percentages between months cannot reliably determine if sales went up or down. The highest percentage of the unit sales for top 300 comics any publisher has ever had was 56.07% by DC in October 2011. In that month, DC released both the second issues of the New 52 relaunched titles, and reorders of every one of the previous month's first issues except for "Men of War."

There were 14 titles selling over 100,000 units, which is the most items over that benchmark since May 2007, which had 15 titles. June 2006 holds the record for the most items selling more than 100,000 units with 18. June 2006 was the second month of the "Civil War: event and the "52" series, as well as having first issues of "Wonder Woman," "Flash, The Fastest Man Alive" and "Eternals." Of October's issues, three were the final remaining installments of "Journey to Star Wars: The Force Awakens: Shattered Empire." Another seven were first issues -- more on that in a minute. Only three of the items, "Secret Wars" #6," "Star Wars" #10 and "Batman" #45, are likely to see similar sales in November. The bottom line is, most of October's high sales are unlikely to be repeated next month.

Marvel offered 28 first issues in October 2015, with average sales of 108,388 units. Four of those first issues ("Spider-Gwen," "Uncanny Avengers," "Unbeatable Squirrel Girl," "Marvel Universe: Guardians of Galaxy") were the second first issues for the title within 2015. Topping the sales for Marvel in October was "Invincible Iron Man" #1 with an unsustainable 279,513 units. How do we know it is unsustainable? First off, nothing other than "Batman" has been able to sustain sales over 100,000 for over a year. Second, and more importantly, "Invincible Iron Man" #2 came in at 28 on the chart with 66,664 units -- a drop of 76.15% from the first issue.

The second best seller for Marvel was "Amazing Spider-Man" #1 with 245,873 units. At rank 10 was "Amazing Spider-Man" #2 with 111,321 units -- a drop of 54.72%. A few more titles with both the first and second issues released in October include "Captain America: Sam Wilson" #1, which sold 62,534 units followed by a drop of 35.68% to 40,224 units on the second issue. "Spider-Man 2099" #1 sold 57,718 units and then dropped 29.48% to 40,701 units with the second issue. The average second issue drop for a mainstream Marvel title in October was 43.94%. Marvel is scheduled to have two dozen first issues in November and another 13 in December. We'll have a lot more data points for second issue drop on Marvel titles in the next few months.

One of the reasons the second issue drops are so large for Marvel is the promotional push on the first issues. "Invincible Iron Man" #1 had at least 10 variant covers beyond the regular cover, while the second issue only had two variants. "Amazing Spider-Man" #1 had 11 variant covers, while the second issue of that title only had two. "Captain America: Sam Wilson" #1 had four variant covers, and the second issue had two. "Spider-Man 2099" #1 had three variant covers and the second issue only two. That smaller gap in the number of variant covers between the first and second issue is part of why the drop on those two titles wasn't as large as it was for the ones with close to a dozen variant covers on the first issue and a fraction of that on the second issue.

Collectability is a major sales factor, one that is much larger than is healthy for the industry as the revenue stream created by variants is non-trivial. In addition to the first issue variants, there are themed variants. At DC, many October releases had Monster themed variant covers. Given sales were down on almost every DC title in October, it stands to reason the Monster theme variants were not as popular as September's Green Lantern 75th Anniversary covers. Perhaps the Looney Tunes variants will do better in November.

A percentage of the sales charts we see every month is directly based on these variant covers, and how big of a percentage is challenging to determine from the data Diamond releases. The retailers and publishers should have a better idea how large that percentage is, because if the collectability bubble bursts, as it did in the '90s, that percentage of the sales, however large it is, could rapidly disappear. Along with it could go another percentage of sales for the items those collectors were actually reading, should those people leave the hobby entirely. With Marvel titles averaging 61,393 units, DC titles averaging around 25,988 units and other publishers averaging around 10,749 units in October, you have to wonder, what percentage of sales is too much to lose? Keep in mind, those average sales are for the best month Marvel has had in the last dozen years and is far from typical. In September, for example, Marvel averaged 34,695 units per title, showing how big of a difference relaunching titles with numerous variant covers can make on a book's sales.

The first trade paperbacks of "Star Wars" and "Star Wars: Darth Vader" came out and took the top two slots on the Top Trades list with 21,826 units and 10,142 units respectively. The first "Star Wars" collection sets a new opening month sales record for a Marvel trade during the final order era. The previous best-selling Marvel trade during a single month was "Civil War" in April 2007 with 19,215 units. The strength of the Star Wars franchise on the trades list should help Marvel in a corner of the Direct Market where it traditionally maintains a lower percentage of the sales than DC comics.

If you'd like to listen to an in-depth discussion of the sales data, check out the Mayo Report episodes of the Comic Book Page podcast at www.ComicBookPage.com. In addition to those episodes, every Monday is a Weekly Comics Spotlight episode featuring a comic by DC, a comic by Marvel and a comic by some other publisher. I read around 200 new comics a month so the podcast covers a wide variety of what is currently being published. If you are looking for more or different comics to read, check out the latest Previews Spotlight episode which features clips from various comic book fans talking about the comics they love. With thousands of comics in Previews every month, Previews Spotlight episodes are a great way to find out about things which may have flown under your comic book radar.

As always, if you have any questions or comments, please feel free to email me at John.Mayo@ComicBookResources.com.