Specialized ratios are sometimes used in specific industries. For example, the so-called book-to-bill ratio is closely watched for semiconductor manufacturers. A ratio of .93 indicates that for every $100 worth of chips shipped over some period, only $93 worth of new orders were received. In October 2020, the North American semiconductor equipment industry’s book-to-bill ratio was .97, down from 1.19 in April 2020. What is this ratio intended to measure? Why do you think it is so closely followed?