Imports Have Been Economic
Source: EIA
SFrom 1998 to 2003, the increases in domestic production and imports have been almost equal, with net imports comprising 56% of the supply increase and production supplying 44 percent.  Gasoline imports have been an economic source of supply as implied by refinery utilization being lower in all years from 1999 through 2003 than in 1998.

SIn 1998, U.S. refining capacity utilization was at an historic high and very near maximum input levels during the summer gasoline season.  While utilization has been somewhat lower since then, only modest capability to produce more gasoline has existed during the summer period.  Moreover, refining capacity increases from 1995 to 2003 have not been sufficient to produce the increases in volume of gasoline sold in the United States.  As a result, gasoline imports increased.