BERLIN -- May sales of printed circuit boards in Germany slid sequentially on supply shortages, but still rose 40% year-over-year.

ZVEI PCB and Electronic Systems said sales for the first five months of the year were up 32% versus period last year. Bookings jumped 137% year-on-year, setting a monthly record.

The book-to-bill ratio was a record 1.66 -- the highest mark in the 17 years the trade group has tracked the data. A book-to-bill ratio of 1.66 means that for every 100 euros worth of boards shipped, 166 euros worth of boards were ordered.