NEMA's compact fluorescent (CFL) lamps index retreated for the fourth consecutive quarter in Q1 of 2011, registering a reading of 180.8, a decline of 16.8 percent on a year-over-year basis. Incandescent lamp shipments fared better, showing an increase of 6.4 percent over the previous quarter. With a first quarter reading of 57.0, the index remained unchanged from the same period last year. 
Incandescent lamps remained dominant by increasing to a 79.0 percent share, an increase of 1.1 percentage points over fourth quarter 2010. CFLs gave back market share gained over the last three years decreasing to 21.0 percent, their lowest share since the fourth quarter of 2007.