US carmakers lost ground on their foreign rivals during December as they cut incentives aimed at luring buyers.
The foreigners are coming
Japan's Toyota has now overtaken Ford as the biggest seller of passenger vehicles in the US.
Total demand, meanwhile, accelerated during the month, helping the industry register one of its best ever years.
Analysts are optimistic that the buying trend will continue into 2004, driven by low interest rates, improving job and stock markets, and new models.
The figures didn't go unnoticed as industry leaders met in Detroit for the city's annual car show.
The chief executives of Ford and GM complained on Tuesday that Japan's intervention in the currency markets has helped prop up the dollar and kept the yen artificially weak.
"Frankly, it's time (for Japan) to get off the 'We're going to export everything we make to somebody else'," said Rick Wagoner, GM's chief executive.
"They have a responsibility to shoulder growth domestically", he added.
US car sales totalled 16.7m last year, down from about 18m in 2002.
General Motors, the world's largest carmaker, saw sales drop almost 10% in December compared with the same month a year earlier. They slid 2.3% in the year.
Ford's monthly revenue fell by 8%, while for the year, sales were down 4.6%.
For DaimlerChrysler a 2% gain in December wasn't enough to lift it out of the red.
The company posted a 4% drop for 2003 as a whole.
Toyota, meanwhile, is benefiting from its reputation for reliability.
In December, the company's sales climbed 4.3%.
Good old days
And it's not the only foreign company to get a boost.
Nissan's revenue rose 12% in December, while Porsche reported US sales doubling to the highest levels since 1986.
It's a long way from the good old days when 90% of cars sold in the US were made by Americans in Detroit.
While GM and Ford have been scaling back incentives to help boost profit, they won't completely stop offering deals to customers.
GM recently launched a $25m promotion which gives visitors to its showrooms the chance to win a brand new vehicles such as the Hummer army truck and luxury Cadillac cars.