If you want fuel efficiency, it's hard to go wrong with a German-made car, according to Forbes.com.

In putting together its list of 2009's most fuel-efficient cars across 10 different classes, Forbes put seven vehicles from German manufacturers on the list.

Four of the German cars topped their classes while three tied for the lead, including in the convertible class, where two Audi vehicles, the TT Coupe and the Roadster, shared the honors.

Two German diesel models especially stood out in the list: The Volkswagen Jetta TDI tops the hatchback class and the Mercedes-Benz E320 BlueTEC was the most fuel-efficient luxury sedan.

"Diesel models feature simpler engine design, less energy lost to heat and a more efficient way to utilize fuel," Karl Brauer, editor-in-chief of Edmunds.com, told Forbes. "They're poised for more success today because of the price of fuel, because of clean diesel technology, and because diesel models are great to drive."

German cars on the list didn't excel just because of their fuel type, though. Daimler AG's Smart fortwo pure relies on a compact vehicle frame for efficiency, delivering a 36 mpg rating. It's also the cheapest car on the list, coming in at a base manufacturer suggested retail price of $11,990.

But consumers are also turning to Japanese cars when seeking the most bang for their fuel buck. And for good reason, since the Toyota Prius, which made the list as the most-fuel efficient hybrid, tops all comers with an EPA combined fuel economy of 46 mpg.

The Prius was the only Japanese car to top its class, although two other vehicles, the Acura TSX and Toyota Avalon, tied for tops in the upscale sedan and large sedan classes respectively.

Even though it finishes second only to the Prius in gas mileage at 42 mpg, the Honda Civic hybrid failed to make the list since it didn't top its class.

One South Korean model, the Hyundai Elantra, topped its class while the Chevrolet Impala LS (tied for best in the large sedan class) and the Chevrolet HHR LS (tops for SUVs) represented American automakers.