NEMA’s shipment indexes for high intensity discharge (HID) lamps declined by 11.7, 17.1, and 0.9 percent on a year-over-year basis for sodium vapor, mercury vapor, and metal halide lamps, respectively. For the year as a whole, shipments of mercury vapor lamps also declined for the fourth consecutive year, dipping 2.7 percent compared to 2009. Conversely, sodium vapor and metal halide HID lamp shipments increased during 2010 by 1.1 and 5.2 percent, respectively.

Sodium vapor lamps showed an increase in market share of nearly 2.0 percentage points ending the quarter at 33.2 percent of HID lamp shipments. The share of metal halide lamps registered a reading of 61.8 percent, a decline of 1.5 percentage points. Mercury vapor lamps gave up market share as well declining by 0.5 percentage points to 5.0 percent for the fourth quarter.