NEMA’s high intensity discharge (HID) lamp indexes for each of the major lamp types (sodium vapor, mercury vapor, and metal halide) increased on a year-over-year basis during the first quarter of 2010. HID sodium lamps posted a 7.5 percent gain while mercury lamps showed a more modest gain of 1.3 percent. Metal halide lamps rebounded from a record low set in first quarter 2009, increasing by a robust 16.8 percent. 

The market share of metal halide lamps remains steady constituting six out every ten HID lamps sold. Sales of sodium vapor HID lamps represent approximately one third of all HID lamps. The share of mercury vapor lamps, the oldest type of HID lighting, has vacillated around 5.0 percent since 2008. Mercury vapor lamp sales are likely to continue at a depressed level due to the U.S. ban on the manufacturing and sale of mercury vapor lamp ballasts.