User blog comment:Miskos3/Episode 277: Message of Fire, Review & Series Review/@comment-73.191.17.103-20160327115410/@comment-3987368-20160327153436

As far as the western market goes, the information we get about top-selling manga is always arranged by volumes. I've yet to see a "by series" list like we get semi-annually for sales in Japan. This makes finding out the "most popular manga" in the US a difficult task at best.

Here is a list of 2014 manga volume sales in the US though, showing that Attack on Titan pretty much dominated the competition with 7 of the top 10 spots.