NO ONE OIL FIRM DOMINATES US MARKET

No single American oil company has as much as a 9 percent share of the nation's gasoline market, according to a study by the American Petroleum Institute. The study shows that Shell Oil Company was the leading US gasoline marketer last year with an 8.15 percent share. Amoco Corporation was second, with 7.38 percent.

Rounding out the top five were Exxon Company, USA, Mobil Corporation, and Chevron Corporation.