Sales of hybrid gas-electric cars in the US doubled last year according to industry analysts JD Power.

A total of 85,699 sales of seven different models were recorded in 2004, up 97.3 per cent from the 43,435 sold in 2003, Mercury News reports.

Furthermore JD Power believes that similar growth rates will be achieved for a number of years to come.

Toyota's Prius accounted for 63 per cent of the hybrid market, which translates into sales of 53,991 units.

However, new hybrid models such as the Ford Escape sport-utility, the Honda Accord sedan and the Chevy Silverado and GMC Sierra pickups all performed well after going on sale in 2004.

JD Power analyst Anthony Pratt commented: "The fact that all vehicle manufacturers have a hybrid strategy is significant.'