NEW YORK, Jan. 4 (Kyodo) — Toyota Motor Corp. saw its new car sales in the United States fall 6.7 percent in 2011, down for the fourth straight year, but its U.S. rivals enjoyed double-digit growth as overall sales in the market increased, according to data released Wednesday by a U.S. research firm.

Toyota was forced to reduce production in North America for about six months until September due to parts shortages caused by the March disaster in Japan, cutting sales by about 400,000 units. Its sales in 2011 totaled 1,644,661 units, with its market share dropping to 12.9 percent from 2010's 15.2 percent, according to Autodata Corp.

The Japanese automaker said it expects its sales in the U.S. market to grow 15.5 percent in 2012 from 2011 to some 1.90 million units, by boosting sales of its new Camry sedan launched last October and by introducing new hybrid and other environmentally friendly models.

Overall new car sales in the United States increased 10.3 percent last year from 2010 to an estimated 12,778,171 units, Autodata said, adding the figure is preliminary as some European carmakers have yet to finalize their data.

Among the "Big Three" U.S. automakers, General Motors Co. sold 2,503,797 units, up 13.2 percent, retaining the top position for the entire year with a market share of 19.6 percent.

Ford Motor Co. saw its sales climb 11.0 percent to 2,143,101 units for a 16.8 percent market share, remaining the second-biggest carmaker.

Chrysler Group LLC's sales jumped 24.3 percent to 1,349,345 units for a market share of 10.6 percent as it took the No. 4 slot from Honda Motor Co., whose sales suffered a 6.8 percent drop to 1,147,285 units after posting a 6.9 percent rise in 2010. With a share of 9.0 percent, Honda fell to fifth spot.

The combined sales of the three U.S. carmakers increased 14.7 percent to 5,996,243 units for a combined market share of 46.9 percent, compared with 45.1 percent in 2010.

Among other Japanese carmakers, Nissan Motor Co. continued posting robust sales growth, with a 14.7 percent increase to 1,042,534 units for a market share of 8.2 percent, following an 18.0 percent jump in 2010.

Mazda Motor Corp.'s sales rose 9.1 percent to 250,426 units, while Fuji Heavy Industries Ltd., known for its Subaru brand, saw its sales edge up 1.2 percent to 266,989 units.

Mitsubishi Motors Corp. posted a 41.9 percent surge in sales to 79,020 units. Suzuki Motor Corp. sold 26,619 units, up 10.9 percent.

In December alone, new car sales in the United States increased 8.7 percent from a year earlier to an estimated 1,243,965 units, up for the seventh straight month, according to Autodata.