Volkswagen Group of America has sold 100,000 TDI clean diesel vehicles in the U.S. in 2013, reaching the milestone for the first time in a calendar year, the automaker has announced.

The turbodiesel vehicles were sold across 12 Volkswagen and Audi models. These models deliver up to 30% better fuel economy and 12%-30% lower carbon dioxide emissions than gasoline engines, according to the automaker.

In 2013, Audi enhanced its lineup with the new Audi Q5 TDI, A6 TDI, A7 TDI and A8 TDI models. Those models joined the existing Audi Q7 SUV. Next summer, Audi will introduce its most fuel-efficient model—the A3 TDI sedan.

Volkswagen offers clean diesel technology in seven different models, six of which get an EPA estimated fuel economy rating of 40 mpg or more on the highway. The models include the Beetle, Beetle Convertible, Golf, Jetta, Jetta SportWagen, Passat and Touareg.