The continued combination of low gas prices and strong pickup and SUV sales led the average fuel economy of light vehicles purchased in the U.S. in November to fall from October, albeit slightly, a University of Michigan Transportation Research Institute report said.
The average window sticker rating of cars, SUVs, vans and pickups purchased in November was 25 mpg — down from October’s revised 25.1 mpg.
“This decline likely reflects the continuing drop in the price of gasoline in November, and the consequent increased sales of pickup trucks, SUVs and crossovers,” researchers Michael Sivak and Brandon Schoettle wrote in an email.
November’s fuel economy was down 0.3 mpg from a year earlier. However, it marks the 22nd consecutive month that fuel economy was at or above 25 mpg.
While fuel economy is down 0.8 mpg from August 2014’s peak of 25.8 mpg, it is up 4.9 mpg since October 2007, when the institute’s monitoring began.
According to AAA data, the national average of regular gasoline in the U.S. was $2.047 per gallon on Friday, down from $2.728 one year ago.
U.S. pickup sales in November rose slightly, 2.9 percent, from November 2014 to 199,469. SUV sales in November were also up slightly, 2.4 percent, from last year to 102,266.
A second study by the institute tracked September’s average greenhouse gas emissions of each new-vehicle drive in the country. The University of Michigan Eco-Driving Index for September was 0.83, up 0.02 from August.
According to the report, that value indicates that the average new-vehicle drive produced 17 percent lower emissions in September 2015 than in October 2007 but 5 percent higher than the record low of 0.78 reached in August 2014.
This article originally appeared on Automotive News.