Behind the Wheel with Phil Lebeau

Chart of the Day: Most fuel-efficient automakers

The combination of lighter vehicles and more fuel-efficient engines made 2013 model year automobiles in the U.S. go further than ever before on a gallon of gas.

The Environmental Protection Agency last week issued its annual report on the fuel efficiency of cars, trucks, and SUVs for model year 2013. Overall, the average fuel economy of 23.6 mpg increased 1.2 mpg from 2012's models. It's the greatest fuel efficiency recorded by the EPA since it started tracking the data 38 years ago.

Mazda was tops in fuel efficiency, in great part because of its fleet. Compared with most other automakers, the company sells a higher percentage of cars and crossover utility vehicles. Those models, led by the Mazda3, helped the Japanese manufacturer raise its average fuel economy rating to 27.1 mpg.

(Read more: Gasoline? Nat gas? Our car lets you choose: GM)

By comparison, Ford Motor, General Motors and Chrysler posted lower average fuel economies, as they produce a combined 90 percent of the pickup trucks sold in the U.S. and a large percentage of heavy SUVs, which get fewer mpg.

As you check out 2013's most fuel-efficient automakers, keep in mind that they all have to raise their corporate average fuel economy (CAFE) rating to 54.5 mpg by 2025.

—By CNBC's Phil LeBeau. Follow him on Twitter @LeBeauCarNews.

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