The average fuel economy of new light vehicles sold in the U.S. in June was 25.3 mpg (9.3 L/100 km), up 2.5% from same-month 2013 and 20.7% better than the base score of fourth-quarter 2007.

The June result was down slightly from the prior month’s 25.5 mpg (9.2 L/100 km) rating, but still was higher than the first four months of the year.

The average for all cars came to 29.4 mpg (8.0 L/100 km), 3.1% above same-month 2013. The rating slipped 1.0% from May 2014, as the sales mix shifted to less fuel-efficient segments.

Small cars (31 mpg [7.6 L/100 km]) and midsize cars (30 mpg [7.8 L/100 km]) lost market share, and large cars (23 mpg [10.2 L/100 km]) grew in popularity compared with month-ago. Luxury cars posted a small uptick to a best-ever 25.5 mpg (9.2 L/100 km), but increased share of the segment pushed the car average down.

Imported cars showed a 2.7% higher rating than last year. The score for domestic cars rose 3.2%.

The index result for light trucks fell slightly from the previous month to 21.0 mpg (11.2 L/100 km), but was 2.4% above June 2013. The biggest factor in the monthly drop was CUVs, which declined 0.5% in fuel economy to 23.1 mpg (10.2 L/100 km) and lost share to the other, lower-rated segments. Vans had a best-ever score of 20.8 mpg (11.3 L/100 km), but didn’t have a significant positive impact because the segment maintained only a 6% share of the LV market.

Domestically built light trucks averaged 20.5 mpg (11.5 L/100 km), up 2.8% from year-ago. Imported light trucks posted a 0.7% gain to 23.7 mpg (9.9 L/100 km).

Ford was one of the most improved automakers from May, rising 1.3%. Increased share of small cars and electric and plug-in hybrid vehicles boosted the automaker to a record high 24.6 mpg (9.5 L/100 km).

Daimler also posted a 1.3% gain from May, due mainly to growth in car sales over light trucks.

Audi’s increased diesel vehicles raised its rating to a record 23.3 mpg (10.1 L/100 km).

Toyota had the largest decline from May, down 2.0% to 27.7 mpg (8.5 L/100 km). Sales of larger models increased, while hybrid, plug-in and electric vehicle sales fell.

Mitsubishi maintained the prior month’s score of 30.2 mpg (7.8 L/100 km), remaining the highest-rated automaker and the only one above 30 mpg (7.8 L/100 km) (excluding electric-only Tesla).

The national average gasoline price rose for the seventh consecutive month, reaching $3.77 a gallon in June. For each of the last couple months, increases have been less than $0.02, allowing consumers to adjust to the new costs without increased concern about fuel economy in their new vehicles.

Through the first six months of this year, the WardsAuto Fuel Economy Index stood at 25.2 mpg (9.3 L/100 km), a 2.2% improvement from the same period of 2013.

eberger@wardsauto.com