SAN JOSE —North America-based semiconductor equipment manufacturers posted three-month average basis orders of $1.41 billion worldwide in May, up 6.6% from a year ago. Orders were down 2.4% from the revised April figures, the SEMI trade group said. 

The book-to-bill ratio was 1.0, according to SEMI. A book-to-bill of 1.0 means that $100 worth of orders were received for every $100 of product billed for the month.

The three-month average of worldwide billings in May was $1.41 billion, up 30 basis points from the final April levels and up 15.1% over May 2013.

The SEMI book-to-bill is a ratio of three-month moving averages of worldwide bookings and billings for North American-based semiconductor equipment manufacturers. Billings and bookings figures are in millions of U.S. dollars.