Number of books borrowed/total number of libraries = book borrowing rate, which refers to the ratio of the number of books borrowed by readers to the number of books borrowed, that is, the average number of books borrowed by each reader throughout the year. The book circulation rate refers to the percentage of books and periodicals borrowed by readers for public borrowing in a certain period (semester and school year). The calculation formula is: (total number of books borrowed/total number of borrowers) * 100%.