Top 5 Fuel-Efficient cars of USA

These cars were ranked in their class for fuel economy,cost,comfort and performance in America.Here is a list according to a study done by Forbes :
1.The Chevrolet Corvette ranks high among car enthusiasts for its speed, performance and looks.
2.Mercedes-Benz S-Class,
3.Lexus IS 250/350,
4. Mini Cooper Clubman and
5.Toyota Prius