To my knowledge, anything with an ISBN counts towards book sales. It's funny though how many things have an ISBN that you wouldn't call a book. Playing cards, empty notebooks, adult coloring books, etc all count towards book sales. That fad of adult coloring books from about 9 years ago boosted book sales quite a bit.
> Adult coloring books were the main driving force behind the rise of adult nonfiction 12% sales growth during the first half of 2016 compared to the first half of 2015.
> Adult coloring books were the main driving force behind the rise of adult nonfiction 12% sales growth during the first half of 2016 compared to the first half of 2015.
https://wordsrated.com/adult-book-sales-statistics/#:~:text=....