Petroleum Industry—Summary: 1980 to 2005
http://www.census.gov/compendia/statab/tables/08s0874.pdf
Crude Oil, Natural Gas, and Natural Gas Liquids—Reserves by State:
http://www.census.gov/compendia/statab/tables/08s0877.pdf
Gas Station statistics
http://www.census.gov/Press-Release/www/releases/archives/county_business_patterns/012181.html