So... no. This isn't really something I have numbers about, I'm afraid. I'm not a data analyst; I'm glorified data entry. I can notice funny things about individual books from authors I already know (like Sanderson—so when I saw the YA editions of Mistborn were a thing I was able to investigate...
According to the publisher, Era 1 is either YA or adult depending on which cover you bought... :shifty2:
No, seriously. I work in book data. There are subject codes we use industry-wide, and the fiction codes are separated out by audience: adult, young adult, and juvenile. Era 1 was...