BANNOCKBURN, IL -- The 90-day moving average of November shipments of bare PWBs fell 7% year-over-year and orders slumped 18.8%, according to the latest survey of the nation's board fabricators.

For the month, rigid shipments dropped 5.8% and bookings fell 17.3%, while flex circuit shipments dropped 22.6%  and bookings plunged 36.8%, IPC said.

Through November, rigid shipments are up 2.4%, and bookings are down 3.8%. Flex circuit shipments are up 5.8% and bookings are down 5.5% versus last year.

The monthly book-to-bill ratio slipped to 0.94. The ratios are calculated by dividing the value of orders booked over the past three months by the value of sales billed during the same period. A ratio of more than 1.0 is considered a sign of future expansion.

Rigid PWBs make up an estimated 90% of survey.About 14% of the value of the PWBs covered in the survey are imported by brokers, IPC said.

Overall, shipments are up 2.6% and bookings are down 3.9%.

IPC said in a statement it expects PWB revenues in 2008 will be flat with 2007.