Barrel (unit) continued to use the same size barrels. In the worldwide oil industry, an oil barrel is defined as 42 US gallons, which is about litres or 35 imperial gallons. Oil companies that are listed on American stock exchanges typically report their production in terms of volume and use the units of bbl, Mbbl (one thousand barrels), or MMbbl (one million barrels) and occasionally for widest comprehensive statistics the Gbbl (or sometimes Gbl) denoting a billion. There is a conflict concerning the units for oil barrels (see ). For all other physical quantities, according to the International System of Units, the
History of the oil shale industry in the United States as Americans bought record numbers of automobiles. Despite steadily growing domestic petroleum production, the American oil industry could not supply the rapidly growing demand, especially for gasoline, and the country had to import increasing amounts of oil, raising prices, and causing widespread speculation that petroleum would be soon exhausted. America was quickly running out of petroleum and into a permanent state of energy scarcity – or at least many experts said so. The average price of crude oil in the United States more than tripled, going from $0.64 per barrel in 1915 to US$2.01 in 1920. Domestic oil production grew,