WASHINGTON—Automakers often show off environmentally conscious vehicles aimed at impressing government officials at the Washington Auto Show, but this year it may be a fruitless endeavor.

With gas prices remaining low and the Trump administration possibly set to loosen federal fuel-economy standards, there’s no longer momentum behind hybrids, electric and other hyper-efficient vehicles.

Sales of hybrid vehicles alone fell 9.7% to 347,029 in 2016, according to figures compiled by HybridCars.com and market-research firm Baum & Associates. Although sales of electric vehicles rose, they still represent less than 1% of the market.

Evercore ISI analyst George Galliers estimated that electric vehicles and plug-ins will represent only 3.5% of global auto sales in 2020, though he projected that would increase to 10% by 2025. “The sad truth is: customers don’t pay more money  for electric cars and they certainly don’t pay for better fuel economy,” Galliers said in a note to investors.

As Americans pile into thirstier crossovers, pickup trucks and sport-utility vehicles in record numbers, auto companies are still plugging away with new, small-volume “green” models.

At press conferences Thursday at the show, Toyota showed off the recently released Prius Prime plug-in. Fiat Chrysler highlighted the plug-in version of its Chrysler Pacifica minivan. And Hyundai held a press conference to boast about the electric, hybrid and plug-in versions of its new Ioniq sedan.

“It’s always been these kinds of vehicles at the auto show” in D.C., Autotrader analyst Michelle Krebs said. “But they aren’t selling well, they’re being heavily discounted and they’re just a very tiny share of the overall market.”

Trump vowed to pare back environmental standards during a meeting Tuesday with the CEOs of General Motors, Ford and Fiat Chrysler.

Although the Environmental Protection Agency asserted in the final days of the Obama administration that current fuel-economy standards are important and achievable, automakers are pressing the Trump administration for a review. The agency estimated the regulations will lead to average fuel economy of 36 miles per gallon in 2025, up from about 25 mpg today.

“What we want is an honest … review” of the standards, Toyota North America CEO Jim Lentz said in an interview earlier this month.

But supporters of the fuel-economy regulations reject the premise that they need to be rolled back to aid the auto industry. They say better gas mileage is good for Americans’ pocketbooks and for the viability of the manufacturers.

“We know gas prices will eventually go back up, and if they don’t focus on fuel efficiency, the U.S. car makers will be in the same position as they were years ago when their lots were filled with unsold SUVs and pickups,” said Jack Gillis, director of public affairs for the Consumer Federation of America.

Nonetheless, there are multiple reasons why hybrids, electrics and plug-ins aren’t going away altogether:

•Range is improving. Electric vehicle batteries are getting better and cheaper, as exemplified by the 238-mile-range in the Chevrolet Bolt.

“The Bolt EV is an important part of a full-line strategy for Chevrolet — for us it is about offering consumers choice,” says Chevrolet spokesperson Afaf Farah. “And for Chevrolet, innovation is at the heart of everything we do .”

•The driving experience is improving. Hyundai Vice President Mike O’Brien acknowledged that hybrids and electrics are “not really exciting cars to drive.” But he argued that the Ioniq’s driving experience measures up to conventional engine vehicles. “We’re trying to overcome the objections customers have to electric vehicles,” he said.

•It’s a global business. Environmentalism is flourishing in other parts of the world, where fighting climate change is a virtue and carbon emission standards are getting tighter.

“These are all global players and they’ve got to play in all the markets. In that regard they’ve got to continue with their plans,” Autotrader’s Krebs said.

•California remains a catalyst for environmentally conscious cars. The state’s fuel-economy requirements have caused automakers to introduce special electric and hydrogen models to earn emissions credits to qualify with regulations. German automaker Volkswagen even agreed to deliver new zero-emission vehicles in California as part of its settlement with the state’s regulators and the U.S. government over its diesel emissions scandal.

“California has dug in its heels,” Krebs said.

Follow USA TODAY reporter Nathan Bomey on Twitter @NathanBomey.