A 33% "rate bubble" applied between $74,850 and $155,320 for married filing jointly, between $37,425 and $117,895 for married filing separately, between $44,900 and $93,130 for singles, and between $64,200 and $128,810 for heads of households, the purpose being to recapture the revenue that upper-income taxpayers had saved by applying the 15% rate."