BANNOCKBURN, IL, Jan. 3 -- The November 90-day moving average shipments of all types of circuit boards 2004 rose 4.1% year-on-year, according to the latest poll of U.S. PCB fabricators. Bookings slumped 27%, however, due to seasonality and intense competition from Asian manufacturers.

The domestic book-to-bill ratio was 0.96, down from 1.05 in October. November marked the first time the indicator dropped below 1.0 since April 2003, said IPC, which tracks the data.

The ratio is based on data collected by IPC from rigid and flex producers and is calculated by dividing three months worth of orders by sales. A ratio over 1.0 is considered an indicator of rising demand.

Separately, the ratios were 0.88 for rigid PCBs and 1.28 for flexible circuits.

Despite the November dropoff, rigid boards, which are estimated to make up about 82% of all domestic PCBs, are showing some improvement. Year-on-year rigid shipments are up 17.8% and bookings are up 8%, while flexible shipments have grown 72.5% and bookings are up 88.7%.

Combined, shipments and bookings are up 28.5% and 24.8%, respectively, this year. Sequentially, shipments dropped 5.2% and bookings fell 23.3%.

Flex sales include some value-added services in addition to the bare flex circuits.

In a statement, IPC cautioned that month-to-month comparisons should be made with caution as they may reflect cyclical effects.