that really highlights how poorly xbox titles do in japan.
i dont think they like being the last to get the games. although it is a taste of their own medicine(games like final fantasy and metal gear were released almost a year or more before we got our hands on them).
If you can’t get your hands on official sales lists, one of the easiest things to do is to google to find press releases about launches of new games. When a sequel is launched the press release will usually say how much its predecessors have sold.