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 the first quarter of 2018, the North American semiconductor equipment industry’s book-to-bill ratio was 1.14, down a 2017. The most recent low occurred in October 2016 when it reached .91. What is this ratio intended to measure? Why do you think it is so closely followed?