DETROIT (AP) — Americans bought more cars and trucks last year, inspired by easier credit, an improved economy and the desire to replace aging vehicles that got them through the Great Recession.

Sales rose sharply for Detroit's three carmakers and for Japan's Nissan in 2011, aided by a surge in November and December. Analysts expect that momentum to continue into 2012.

Low interest rates, looser credit standards and pent-up demand are driving demand. The average age of a car on U.S. roads is the oldest ever, closing in on 11 years. Americans want to trade in those older vehicles now that a tentative recovery has begun and they're feeling a little more secure about jobs and finances.

Buyers also were drawn out by an array of high-quality small cars with nice, roomy interiors and more features than in the past. That made it easier to downsize from bigger cars amid high gas prices. Pickups also sold well as business began to replace the trucks they need to haul equipment.

Car companies want sales to keep growing following a nearly 30-year low in 2009. The economy benefits from healthy car demand because it promotes spending on big-ticket items and creates jobs.

After final figures are tallied late Wednesday, U.S. auto sales should rise to around 12.7 million in 2011. That's a 10 percent jump from 2010 and 22 percent from 2009, when the U.S. auto industry and the financial system were in peril. Sales are almost certain to rise again in 2012, perhaps as high as 13.8 million, which would mark the third straight year of growth.

"Over the course of the fourth quarter of 2011, clear signs emerged that U.S. consumers are more confident and that other underpinnings of our economy are either stable or slowly improving," said Don Johnson, GM's U.S. sales chief.

Chrysler led the 2011 sales gains with a 26 percent increase, followed by Nissan at 15 percent, GM at 13 percent and Ford at 11 percent, the companies reported Wednesday.

For December, Chrysler sales surged 37 percent from a year earlier on strong demand for the Jeep Wrangler and the Chrysler 200 sedan. GM was up 5 percent for the month, aided by the Chevrolet Cruze compact and pickup sales. Ford sales rose 10 percent, led by the new Explorer SUV. Nissan sales rose nearly 8 percent for December.

Chrysler Group LLC's strong showing for December capped a remarkable turnaround under its new Italian ownership. And it's expected to jump ahead of Honda as the No. 4 U.S. automaker in 2011.

Chrysler and GM nearly ran out of cash in 2009 and needed government help and a trip through bankruptcy protection to survive.

Chrysler, now majority owned by Fiat SpA, sold 1.37 million vehicles last year, about 284,000 more than in 2010. It has introduced 16 new or revamped models in the past two years, vehicles that have fueled its recovery.

Sergio Marchionne, CEO of Chrysler and Fiat SpA, is predicting a net profit for 2011 of $600 million.

"Over the past 12 months, we successfully changed the conversation from Chrysler's survival to products and service that consumers expect and want from a great American automaker," Marchionne said in an e-mail to employees.

Nissan sold just over one million cars and trucks last year, its best calendar year ever. The company said it sold 944,000 Nissans and more than 98,000 of its Infiniti luxury cars and SUVs. Previously, 2007 had been the company's best year.