Year	Average Mile Per Gallon
1978	19.9
1979	20.3
1980	23.5
1981	25.1
1982	26.0
1983	25.9
1984	26.3
1985	27.0
1986	27.9
1987	28.1
1988	28.6
1989	28.1
1990	27.8

Source: The Christian Science Monitor, March 18, 1991, p. 6, from the U.S. Environmental Protection Agency.

The table above shows the average miles per gallon achieved by all automobiles made in the US and abroad.

As is clearly indicated by the table, the average miles per gallon has been increasing over time.  This is partially due to improved automobile technology, and partially to increased consumer demand for better mileage.

Firms in the United States produced automobiles that consumed large amounts of gasoline back when gas was cheap.  Later, as gas prices rose and foreign companies produced more fuel-efficient cars, US firms also had to adopt more fuel-efficient designs.