The crumbling U.S. economy and the plummeting price of fuel are two of the major factors behind a sudden drop-off in sales of hybrid vehicles in the U.S. market, and the falling popularity of hybrids has auto industry executives worried once more. Data from 2008 now shows the segment fell 9.9% for the year.

Last year, when the price of fuel in the U.S. passed the $4 per gallon mark, hybrids were on the wish list for almost every major carmaker without them in their lineup. But now, with fuel prices back to a more manageable $1.84 per gallon, average consumers are less inclined to buy more expensive hybrid models, especially in light of the current economic downturn affecting the majority of Americans. Only 315,761 of the cars were sold in total last year, accounting for 2.4% of the overall U.S. market, reports Automotive News.

The current slew of hybrids on the market tend to sell for several thousand dollars more than conventional cars, and even with government tax credits consumers are no longer as enamored with the hybrid vehicle as they once were.

On top of this, companies such as Toyota have already reached the limit for government tax credits for their hybrid cars, meaning that their hybrid models are more expensive than ever. Despite this, about 75% of the hybrids sold in the U.S. last year were Toyota-branded.

An analyst for Ford recently summed up the fuel-price situation neatly, stating that "the lower gas prices are, the tougher the proposition is to pay a premium for a hybrid engine." The news is not good for environmentalists, who were sure that the SUV-buying public had seen the error of their ways when fuel prices reached record levels in 2008 - now green groups and auto industry executives are actively petitioning the government to increase taxes on fuel to make hybrids more attractive.