Growth in China's vehicle sales slowed to an annual 9.9 percent in July, an industry group said Friday, as the world's largest car market entered its low season.

Sales totalled 1.52 million last month, the China Association of Automobile Manufacturers (CAAM) said in a statement, a slowdown in growth from June's 11.2 percent improvement.

Sales for the first seven months totalled 12.30 million units, the group said, up 12.0 percent from a year earlier but lower than the 12.3 percent growth registered in the first half.

Automakers usually carry out equipment maintenance and send workers on holiday to avoid China's hottest weather in late July and early August, CAAM said in explanation of the slowdown.

Monthly passenger vehicles sales grew 10.5 percent year-on-year to 1.24 million units, the statement said, adding Chinese-brand sales increased 5.8 percent to 435,500 units to give them a 35.2 percent market share.

It was their lowest share of the market since the global financial crisis in 2008, the group said, adding their situation was "grim".

Among foreign brands, German carmakers had the largest share with 21.4 percent, followed by Japanese companies on 17.6 percent and US firms with 13.6 percent.

China became the world's largest auto market in 2009.

Consulting firm McKinsey forecasts the country's passenger car market to grow an average of eight percent annually through to 2020, when sales will reach 22 million.

Foreign automakers have announced plans to expand in China, where increasing wealth is giving consumers more money to spend.

US automaker General Motors announced in June it would invest $11 billion in China through 2016, as it broke ground on a plant to produce luxury Cadillacs.

And in May German auto giant Volkswagen broke ground on a new plant in the central city of Changsha, due for completion at the end of 2015, with an annual output capacity of about 300,000 vehicles.