In its monthly report, the University of Michigan Transportation Research Institute indicates that the average fuel economy for light vehicles declined to 25.2 mpg in April, down from 25.1 mpg in March.

Overall, fuel economy ratings were down 0.6 mpg from a peak of 25.8 mpg in August 2014 but remain up 5.1 mpg from a low of 20.1 mpg recorded when the institute began monitoring in October 2007.

Michael Sivak, Director of Sustainable Worldwide Transportation at the university, concludes in the release that the dip “likely reflects the increased market share of pickup trucks and SUVs.” SUV sales were up 5.1 percent to 110,520 units and pickup truck rose 12 percent to 232,647 units in April compared to the same period in 2015.

The University of Michigan Eco-Driving Index (EDI) stood at .81 in February, a decline of 0.03 from January 2016. The index estimates the average emissions of greenhouse gases generated by U.S. drivers on a monthly basis.

Overall, the EDI value for February was 19 percent lower than emissions reported compared to October 2007 but up 3 percent over record lows reached in August 2014 and August 2015.