US registrations for new hybrid vehicles rose to 199,148 in 2005, a 139% increase from 2004, according to RL Polk & Co.

Overall, the hybrid category accounts for just over 1% of all new vehicle registrations in the US.

Although competition is hotting up, Toyota dominates the market. Its Prius was the top seller, accounting for 52.6%, while its luxury brand Lexus' RX400h was third with 9.7% of all hybrid registrations, giving Toyota and Lexus a combined 70.7% market share.

The second best-selling model was the Honda Civic hybrid sedan with 12.8% of the market.

California (where pro-environment movements are strong) continues to lead the way for hybrids with 52,619 new registrations in 2005, up from 25,021 in 2004. The state accounts for 26.4% of new hybrid vehicles. Second was Florida (perhaps because it is home to a huge number of cost-conscious retirees), but sales there were much lower at 10,470.

In a statement, RL Polk raised the question of the potential for aftermarket business. Since 2000, there have been nearly 392,000 new hybrids registered in the US.

"With roughly 50% of that five-year volume coming in the last year, significant aftermarket opportunities aren't expected until 2009. Until then, franchised OEM dealerships will likely see the bulk of the repair business based on manufacturer warranties," said Lonnie Miller, the company's director of industry analysis.