Chicago area. Our data is revealing in this respect. The top two recipients of crude oil from the Gulf Coast are Texas and Louisiana; however, the third and fifth largest recipients are Illinois and Indiana, respectively, while New Jersey and Pennsylvania are seventh and ninth. The largest recipient of foreign crude oil is California while the second through fourth largest are Pennsylvania, New Jersey, and New York. Thus, refineries in the midwest are heavily "dependent" on domestic crude while coastal refineries obtain roughly half their receipts of crude oil from foreign sources. These considerations, together with the fact that a market based on Gulf Coast production is geographically distinct only under the weak form of our test, impels us to conclude that the market for crude oil is international.

Examination of data on coal shipments revealed a tendency for the scope of geographic markets to increase. This trend toward increased geographic scope is "artificial" to the extent it has been induced by antipollution requirements. Nonetheless, such requirements have induced or augmented changes in transportation capabilities which will remain even if air pollution standards are relaxed. Finally, the market for coal is regional only under the weak form of our tests. For these reasons we offer the tentative conclusion that the industries comprising the energy (input) sector—uranium, gas, oil, and coal—are (at least) national in scope.