Shipments of metal halide high intensity discharge (HID) lamps grew by 4.6 percent to 87.1 during the third quarter of 2010. The index showed solid year-over-year growth increasing 5.7 percent. Conversely, sodium vapor HID lamp shipments retrenched 10.4 percent during the quarter to 82.1, the second lowest level on record for the index. Mercury vapor HID lamp shipments increased on a quarter-to-quarter and year-ago basis, albeit from depressed levels. Large variances in the performance of this index are likely because of the relatively low volume of shipments.

Mercury vapor lamps carved out a 5.4 percent share of the HID lamp market, an increase of 1.3 percentage points over the previous quarter. Market shares for metal halide and sodium vapor HID lamps moved in opposing directions during the quarter. Metal halide lamps improved 2.8 percentage points to 63.3 percent of total shipments while the market share of sodium vapor lamps contracted to 31.3 percent—a decline of 4.1 percentage points.