In 2002, the United States exported only 3.3 million barrels of crude oil; by 2017, exports were 408 million barrels. In December 1975 the Energy Policy and Conservation Act banned most U.S. crude oil exports in an effort to gain some control over supply as a reaction to spiking oil prices. Some exports continued after that date because the U.S. Commerce Department could grant exceptions for some types of oil. In December 2015, Congress lifted the ban on crude oil exports resulting in the rapid rise thereafter.
Sources: U.S. Energy Information Administration, "Petroleum and Other Liquids, Exports" website. Accessed February 22, 2018. 2017 data from the Petroleum Supply Monthly, February 2018, Table 50.