Unit sales of print books rose 9% in 2021 over 2020 at outlets that report to NPD BookScan. 826 million print units were sold last year, a jump of nearly 68 million over 2020 and a whopping 132 million over 2019. The young adult fiction segment had the largest increase, with unit sales jumping 31%, while adult fiction sales rose 26%. Sales in the juvenile fiction category increased 10%.