Drop in Semiconductor Book-to-Bill Ratio: The ratio fell to 1.06 in September from a revised 1.09 in August, the Semiconductor Industry Assn. said. It was the 11th straight month that orders outpaced shipments for chip makers doing business in the United States. Orders, or "bookings," rose 0.9% to $1.65 billion in September from $1.63 billion in August. Shipments, or "billings," rose 3.1% to $1.55 billion from $1.51 billion in August. A book-to-bill ratio of 1.06 means that for every $100 worth of chips shipped to the U.S. market, manufacturers received $106 worth of new orders.