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 November 2013, the semiconductor equipment industry's book-to-bill ratio was 1.11, compared to 1.05 during the month of October 2013. The book-to-bill ratio reached a recent low of .75 during October 2012 and a recent high of 1.23 during July 2010. The three-month average of worldwide bookings in November 2013 was $1.24 billion, an increase of 10.1 percent from October 2013, while the three- month average of billings was $1.11 billion, a 4.0 percent decrease from October 2013. What is this ratio intended to measure? Why do you think it is so closely followed?