Worldwide, there were 14.8 million natural gas vehicles by the end of 2011.

Calculation of fuel economy for natural gas vehicles is similar.

The company produced its final natural gas vehicles last month.

Natural gas vehicles could help considerably in meeting such a standard.

Ford was one of the first companies to offer natural gas vehicles.

Never learned to drive, and don't much like riding in gas vehicles, either.

India has a fleet of 1,080,000 natural gas vehicles through December 2010.

Argentina already has more natural gas vehicles than any other country in the world.

At the end of 2009 there were 23,000 gas vehicles and 104 public filling stations.

There are about 30,000 natural gas vehicles on the road in this country, most owned by utility companies.