NEMA’s sodium vapor high-intensity discharge (HID) lamps shipment index declined for the fourth consecutive quarter on a year-over-year basis, retreating 15.8% during Q2 2011. The index value of 77.7 is the lowest reading on record for the series. Mercury vapor and metal-halide HID lamp indexes performed better during the quarter, increasing 2.5% and 2.3%, respectively, compared to the same period last year.
Market shares of the three HID lamps types varied by less than 1.0 percentage point compared to the previous quarter. Metal-halide lamps continued to dominate the HID market with a share of 63.9%. Sodium vapor lamps decreased by 0.9 percentage points to 35.1%. Mercury vapor lamps garnered a 4.7% share, an increase of 0.2 percentage points.