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 oil in California through 1930 from $9.60 per barrel in 1860 to $0.25 per barrel in 1895. American oil companies including Union Oil Company became concerned with this development because oil prices had fallen too low for oil companies to maintain high profit margins. Union Oil Company and other oil companies lobbied local and federal governments to regulate the overproduction in the oil market. Their attempts, however, were futile and no regulation was passed. Oil prices remained around $1 through the end of the 19th century. At the turn of the century, oil production in California continued to rise at a booming rate. In 1900,