I think a lot of people read manga, but I only know 2-3 people personally other than myself that do frequently. I'm not a big anime watcher at all, but I read a lot of manga. I think most people swing the other way

Pretty popular. Any book shop of size has whole manga sections, they sell pretty well.

In Hungary I only saw like 2 manga in bookstores, but I heard some bigger were translated fully like Death note and NGE. (They are long out of print by now)

Usually have to order from german amazon if we want to read physical manga.

@YourFavouriteNPC im buying them purely as epubs. The online seller has at maximum 2 week between the release of an new manga. But they aren't popular enough for smaller bookseller to have even one manga in their assortment.

In Spain manga is a really big thing. Lot's of manga fairs in lots of citys, even towns. Mainly a youth phenomenon, but not exclusively, with many, many adult and arty manga published.