Japanese automaker Nissan has made the biggest leap forward in fuel economy since 2012 while Toyota has fallen from third to seventh place as Subaru and BMW made significant gains in average miles per gallon, according to a report from the U.S. Environmental Protection Agency (EPA).

Automakers have a long way to go to meet the federal government’s 2025 adjusted average corporate average fuel economy (CAFE) target of 40 miles per gallon for all new vehicles sold in the U.S. To reach that goal, automakers would have to improve fuel economy an average 1.6 miles per gallon, more than double the 0.6 mpg average annual growth since 2012.

But the EPA expects fuel economy to improve at a faster rate in the coming years as the price of hybrid and electric vehicle technology improves and becomes more competitively priced. Whether U.S. consumers will gravitate to these technologies, or embrace smaller engines and lightweight materials in bigger SUVs and trucks is a big unknown.

The EPA’s annual trends report on carbon dioxide emissions and fuel economy standards released last week shows General Motors and Toyota were the only mass-market carmakers to improve fuel economy by less than the U.S. average of 2.5 percent from 2012 to 2014. The EPA uses so called real-world estimates, the typical fuel efficiency cars get under normal conditions rather than the optimized ones used by automakers when they market the vehicles.

Nissan, BMW and Subaru have made the best strides in lightweight materials and more efficient transmissions than their rivals. Mazda continues to rank at the top of the list of average efficiency, but its strengths lie in smaller hatchbacks and compacts that get better mileage compared to larger, heavier cars sold by its rivals.

Ford and GM rank low on both improved fuel economy in 2012 and average mpg for 2014 because of their heavy reliance on SUVs and pickup trucks, sales of which have jumped amid improved economic conditions. Ford offers smaller EcoBoost engines for its vehicles and it’s about to introduce a lighter aluminum body 2015 F-Series pickup truck, the country’s best selling passenger car. GM is betting on electric and plug-in hybrid technology as well improved engine efficiencies to bring down its average fuel economy.

Hyundai and Kia were excluded from this year’s report because they’re being investigated for overstating their fuel economy claims.

Read the full report here.