The T5 lamp shipments index published by Rosslyn, Va.-based National Electrical Manufacturers Association (NEMA) registered a reading of 152.0 during the second quarter of 2010, a 41.1% increase from a year ago. The index reclaimed lost ground from the previous quarter, rebounding by 19.8%. T8 lamp shipments also showed robust growth, increasing 12.7 on a year-over-year basis. Conversely, shipments of T12 lamps declined 2.6% and 7.9% for the quarterly and year-over-year comparisons, respectively.

The share of T12 lamps in the linear fluorescent market also declined. T12 lamps accounted for 26.3% of sales, 5.1% points below the 2009 average of 31.4%. T8 lamps increased to a 65.0%, a half point below its all-time high. The portion of the market held by T12 lamps grew to a new high of 8.7%. These market share trends are likely to continue due to the July 1 completion of the phase-out of T12 magnetic ballasts.