<http://schema.org/about>
"The University of Michigan's Transportation Research Institute keeps track of the average fuel economy of new vehicles sold in the United States. It's a bit depressing to see how slowly things are progressing, but at least there is some progress..."^^<http://www.w3.org/2001/XMLSchema#string>
<http://www.treehugger.com/cars/fuel-economy-new-vehicles-sold-us-tops-24-mpg-first-time-ever.html>