SEOUL, Oct. 1 (Xinhua) -- Global auto sales by South Korean carmakers fell last month on less business days, industry data showed Monday.

Global car sales by five South Korean auto manufacturers, including Hyundai, Kia, GM Korea, Renault Samsung and Ssangyong, declined 8.5 percent from a year earlier to 678,738 vehicles in September.

Sales in the domestic market tumbled 17.5 percent to 110,130 units, while car export shrank 6.5 percent to 568,608 vehicles last month.

It was attributed to the Chuseok holiday, the South Korean version of Thanksgiving Day, which reduced the number of working days by four days in September.

Hyundai Motor, the country's No.1 automaker, sold 384,833 vehicles at home and abroad in September, down 6.6 percent from a year earlier.

Car sales by Kia Motors, the No.2 carmaker and Hyundai's affiliate, totaled 233,708 units globally last month, down 6.4 percent from the same month of last year.

GM Korea's global car sales tumbled 13.5 percent over the year to 34,816 units in September, and Renault Samsung's auto sales dropped 44.3 percent to 14,582 vehicles.

Ssangyong sold 10,799 cars in September globally, down 18 percent from a year earlier.