How much of US oil imports are used by consumers (gasoline for our cars) ?

Answer 1

it is not meaningful to ask how much of oil imports are used for consumer gasoline, because after the raw petroleum is imported to refineries, the imported and domestic supplied petroleum is not distinguishable

per this site:
http://tonto.eia.doe.gov/dnav/pet/pet_cons_wpsup_k_w.htm

about half of all the petroleum imported or mined in the U.S., goes to gasoline