General Motors (GM.NYSE) said sales jumped 21% year-on-year in China in May due in part to growing demand for microvans produced by a local joint venture, The Wall Street Journal reported. Sales by General Motors and its China joint ventures were up 1.7% from April to 231,183 vehicles. Sales for the January-May period reached 1.2 million vehicles, up 12% year-on-year. The carmaker’s microvan joint venture, SAIC-GM-Wuling, reported a 34% increase in sales during the month. However, sales of the premium Cadillac brand fell 2.2% in May from a year earlier. Stronger sales figures are an encouraging sign for the country’s auto market, particularly if the government adopts new measures to stimulate auto purchases, said Yale Zhang, managing director of Automotive Foresight, a consultancy.