TOP 100 MANGA

From Diamonds description of the figures: 

Data for Diamond’s sales charts — which include the monthly market shares and all top product charts — are compiled by Diamond Comic Distributors from a universe of over 3,500 accounts, comprised of comic book specialty shops and other merchant stores and buyers. The shops are primarily located in North America, with a percentage of sales also to international stores and buyers located throughout the world. The account base includes not only brick-and-mortar comic book specialty shops, but also Internet stores, chain stores, and other specialty stores.

Unit and retail dollar sales are calculated based upon orders invoiced and shipped to Diamond accounts during any given month, which comprises initial pre-orders, advance reorders, and reorders, minus any copies that are received back from a title marked as returnable.

The Sales Index of selected monthly Best Seller Charts is presented as a comparative tool for retailers and publishers. It presents Diamond’s monthly sales for individual titles in relation to Diamond’s total sales for the issue of DC Comics' monthly Batman comic book. (Batman is used as the control title — with a value of 100 — because sales of Batman remain relatively stable.) This allows for easy comparison to other titles and helps retailers gauge their orders for all other titles. This formula is only a guide, other factors may impact a titles' ability to sell in certain locations and clientele.

via Bleeding Cool

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Scott Green is editor and reporter for anime and manga at geek entertainment site Ain't It Cool News. Follow him on Twitter at @aicnanime.