WASHINGTON  Recession, it turns out, is good for fuel economy.

Gas mileage for 2009 model cars and trucks showed the largest increase since the oil crisis of nearly three decades ago, according to an annual report by the Environmental Protection Agency released on Wednesday.

The report found that the average fuel economy in 2009 model cars, vans, pickups and S.U.V.’s was 22.4 miles per gallon  an increase of 7 percent, or 1.4 miles per gallon, over 2008 figures.

The balance between cars and trucks also shifted, with the light truck segment  including vans, pickups and S.U.V.’s  slipping to 40 percent in 2009 models, a decrease of 7 percent from 2008 and 12 percent from the peak year of 2004, when the “average” car was a light truck. The truck share is now at its lowest level since 1995, the agency said.

The report tracked American car sales by 15 manufacturers, 14 of which showed mileage improvement.

Asian automakers, the report found, outdid their American counterparts, with both Toyota and Nissan showing higher-than-average increases in fuel economy  in Toyota’s case an increase of 2.6 miles per gallon, to 25.4 miles per gallon, in 2009 models; for Nissan, an increase of 1.7 miles per gallon, to 23.6 miles per gallon.