CFA's annual study found the percentage of vehicles getting at least 23 miles per gallon hit a record 50.5 percent for the 2014 model year, compared with just 19 percent in 2009. What's more, 11.6 percent now top 30 mpg, a tenfold increase in just five years. For the first time, there's no single model rated at less than 13 miles per gallon.
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But the auto industry is under intense pressure to move even more quickly, with a federal 54.5 mile per gallon Corporate Average Fuel Economy standard set to take effect by 2025.
Because of quirks in the regulations, manufacturers will be able to miss those numbers by about 10 percent, but will still be stretching to get there. Observers expect to see increased use of alternative fuels and propulsion systems, including battery power, hydrogen fuel-cells and diesels, as well as advanced gas engines, more efficient transmissions, improved aerodynamics and downsizing.
—By CNBC Contributor Paul A. Eisenstein.