Petroleum consumption in kJ

Petroleum consumption in the US in 1990 supplied about 35.6E15 kJ of energy.  Of this quantity, about 14.4E15 kJ was supplied by foreign sources.  The transportation sector is the major user of petroleum, accounting for 23.2E15 kJ of consumption.  Overall automobile fuel economy in the US was about 21 miles per gallon in 1990.  Automobile efficiencies in Europe and Japan were about 27 mpg.  If the US had averaged 27 mpg in 1990, how much less petroleum (expressed as kJ) would have been imported?