The US currently uses about 27 quad of energy for transportation per year, nearly all of which comes from petroleum. The Alaskan oil fields are estimated to have as much as 64 quad of oil. How many years could the Alaskan oil reserves supply US transportation needs at the current rate of use? Some analysts estimate that cars and trucks could be made 60% more efficient than they are currently. How long will the Alaskan oil reserves last if the annual transportation energy demand is reduced by 60%?