NEMA’s T12 lamp shipment index tumbled to 37.5 — a decline of nearly 40% on a year-over-year basis during Q3 2012 — the first quarter following the implementation of the new efficiency standards for general service fluorescent lamps (GSFL). T8s and T12s also posted double digit declines of 26.9% and 19.9%, respectively. Overall shipments during the first three quarters for the combined market were 15.1% lower compared to last year. 

T12 lamps posted a precipitous decline in market share, dipping 8.6 percentage points to 19.2%. T8 lamps absorbed a majority of the market share lost by T12s, gaining 7 percentage points for a share of 69.8%. Garnering the remaining 1.6 percentage points given back by T12s, T5 lamps increased to an 11.0% share.