Automakers posted a solid 9% sales gain in December, an exclamation point that sealed 2015 as the biggest sales year ever for the industry, reported USA Today.

All told, automakers sold 17.47 million new vehicles for the year, Autodata reported, besting the previous record set in 2000 by 68,138 vehicles. Low gas prices, cheap credit, low unemployment, soaring consumer confidence and warm weather fueled a rush into showrooms in December.

"The U.S. economy continues to expand, and the most important factors that drive demand for new vehicles are in place, so we expect to see a second consecutive year of record industry sales in 2016," said Mustafa Mohatarem, GM's chief economist, in a statement.

Still, sales success for individual automakers presented a mixed bag. Detroit's Big 3 fared well for December and the year. General Motors had a 5.7% sales increase in December, Ford Motor saw an 8.3% boost and Fiat Chrysler sales rose 12.6%, according to Autodata. Tesla Motors doubled sales during the month and sold 23,650 of its luxury electric cars in the U.S. for the year, but came in at the low end of its delivery guidance on worldwide deliveries.

Among Asian makers, Toyota saw a 10.3% increase for the month, Honda was at 9.9% and Nissan at 8.7%. But for the full year, they came in lower, with Toyota posting a 5.3% increase compared to the industry average of 5.7%

One laggard was German automaker Volkswagen Group, which still cannot sell diesel vehicles amid an emissions scandal, down 3.4% overall. The automaker's Volkswagen brand sales fell 9.1% in December and 4.8% for the year. The company's Audi luxury brand, which has felt a smaller impact from the scandal, achieved a 6% gain in December and 11.1% for the year. Another loser for the month was Hyundai, saddled with a car-heavy lineup during the SUV surge, down 1.5%.

Consumers continued their exodus from less-lucrative cars into crossovers, sport-utility vehicles and pickups amid low gasoline prices.

At 13.9% market share, the small SUV segment is now the largest category of vehicles in the U.S., trailed by small cars and midsize cars at 13.7% apiece, according to Kelley Blue Book.

"There's no end in sight to those trends," AutoTrader.com analyst Michelle Krebs said. "You're going to hear the same broken record next year."

Crossovers like the Toyota RAV4, the Nissan Rogue and the Jeep Renegade delivered a robust showing in December.

"The segment is in demand with Baby Boomers and Millennials both looking for increased utility. We think this is a long-term trend," Ford sales analyst Erich Merkle said on a conference call.

Unlike 2000, when automakers were piling on discounts to sell vehicles despite a strong economy, the industry is financially fit and has spurned steep incentives. Average incentives rose 3.9% in December, compared with a year earlier, to $3,063 per vehicle, according to TrueCar.

Toyota division general manager Bill Fay told reporters it was a "standout year," though he projects sales to "start to level off a bit" in 2016.

Even as crossovers gain, the industry's stalwart full-size pickup trucks have also flourished, in addition to new midsize pickups.

The Ford F-Series pickup, the most popular vehicle in the U.S., rose 14.6% to 85,211 units in December. Sales were up 3.5% for the year to 780,354.