Average U.S. Fuel Economy Shows Monthly Decline in December 

Report from University of Michigan an indication that Americans are loving their gas-guzzling vehicles again.

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The average fuel economy of new cars and light trucks sold in the U.S. declined some last month, reflecting consumer appetite for SUVs and other larger vehicles, a report showed.

The average fuel economy fell to 25 mpg, down 0.2 mpg from the revised number for November, according to the data from the University of Michigan Transportation Research Institute. 

The national gas price average is currently around $2.49, which is lower than four years ago when prices were more than three bucks a gallon.

The decline in the December number likely illustrates the larger count of light trucks in the sales mix compared to passenger cars, Michael Sivak head of the university's Sustainable Worldwide Transportation research group, told Reuters.

Sales of light trucks in the U.S. climbed 4.3 percent to about 10.9 million in 2017, while sales of passenger cars slid about 11 percent to 6.3 million, according to Reuters.

The average fuel economy of new vehicles sold last year was 25.2 mpg, the same as in 2016, according to the University of Michigan report. 

The monthly decline is the first since the university began tracking average window sticker fuel economy in 2007. Overall, it's gone up by 4.9 mpg.