Young Adult

term often used for Teenager Market, esp in Book Publishing

Sept'2015 - looking at Amazon stats

all of top-100 are Fiction, except for an ACT book and an AP-Psych book, and a D And D players' manual, and a book by YouTube-rs Dan And Phil (that's actually a pre-order).
similar for new releases
within the Education/Reference, it's mostly (in the top-20) Standardized Test-prep, plus 7-Habits, plus Ben Carson's book!

Bill Seitz