China's auto sales rose 9.9 percent year-on-year to 1.52 million units in July, the China Association of Automobile Manufacturers (CAAM) announced Friday.

Although the volume marked a 13.6-percent drop on a monthly basis, the CAAM said the still robust year-on-year growth suggest "relatively stable" momentum in the market.

Output surpassed sales by 67,000 units in July, as producers increase stocks to prepare for equipment maintenance usually conducted in late July and early August, the hottest period in which most workers were sent on holiday, the CAAM said.

In the first seven months, sales totalled 12.3 million units, an increase of 12 percent from the same period last year, but slower than the 12.3-percent rate seen in the first half.

Auto output in the January-July period rose 12.46 percent from a year ago to 12.36 million units, according to CAAM.