Japanese automakers marked steady increases in sales of new vehicles in the United States this year as the overall market exceeded 15 million units for the first time in six years, data by a U.S. research company shows.

Toyota Motor Corp. posted a 7.4 percent gain to 2.236 million units for the second consecutive annual increase, Autodata Corp. said Friday.

Toyota's sales were at their highest since 2007, when it sold 2.62 million units, thanks to strong demand for its mainline SUVs and fuel-efficient small models. Toyota ranked third in sales among all automakers in the U.S. market.