Note: Because of the differences in the time periods during which the National Petroleum News (NPN) collects retail outlet data from the States and the Energy Information Administration (EIA) collects State-level sales volume data, the NPN data are associated with EIA data for the previous year. For example, NPN outlet numbers for 1991 are associated with EIA 1990 volume data and all are assigned to 1990.
Sources: Retail outlets: NPN, Market Facts '96 (mid-July 1996), p. 120 and Market Facts 2000 (mid-July 2000), p. 120. Sales volume: EIA, Petroleum Marketing Annual, DOE/EIA-0487 (Washington, DC, 1990-1999), Table 48.