Orders for computer chips rose last month.

Business conditions in the U.S. semiconductor market continued to improve in May, with the book-to-bill ratio reaching a three-year high, the Semiconductor Industry Assn. reported. The index for May was 1.26. The last time the indicator was this high was in May, 1984, when it stood at 1.27. The figure means that for every $100 worth of computer chips shipped, $126 in new orders were received. April’s book-to-bill ratio was revised upward to 1.22 from 1.20. Industry analysts had been expecting the ratio to be flat at about 1.20 for the three months ended in May.