What happened to American fuel economy in 1975

Through the Energy Policy and Conservation Act of 1975, Congress established fuel economy standards for new passenger cars starting with model year.

Through the Energy Policy and Conservation Act of 1975, Congress established fuel economy standards for new passenger cars starting with model year (MY) 1978. These standards were intended to roughly double the average fuel economy of the new car fleet to 27.5 mpg by model year (MY) 1985.