These listings are based on computer-processed sales figures from 3,050 bookstores and from representative wholesalers with more than 28,000 other retail outlets, including variety stores and supermarkets.

The list is based on computer-processed sales figures from 2,000 bookstores and from representative wholesalers.

In 1992, the survey encompassed over 3,000 bookstores as well as "representative wholesalers with more than 28,000 other retail outlets, including variety stores and supermarkets."

The paperback listings also include computer-processed sales figures from representative wholesalers serving more than 40,000 retail outlets.