BEIJING, Jan. 17 (Xinhua) -- The assets of China National Petroleum Corporation (CNPC) hit 1.54 trillion yuan (212.4 billion U.S. dollars) at the end of 2007, up 7.1 percent year on year. At an annual work meeting here on Thursday, Zhou Jiping, CNPC deputy general manager, said domestic exploring and drilling of crude oil and natural gas remained the chief source of the company's profit last year. In 2007, sales of natural gas grew 21.3 percent over the previous year and became CNPC's fastest-growing business, he said. CNPC's newly-installed production capacities of crude oil and natural gas hit 13.66 million tonnes and 10.3 billion cubic meters, respectively, last year. Profit generated by overseas exploration and drilling also increased quickly, Zhou said without elaborating. With overseas projects extending to Africa, central Asia, the Middle East, America and Asia-Pacific region, the company earlier this month vowed to speed up its overseas expansion while maintaining domestic output growth. The CNPC currently has 69 cooperative projects in 26 countries. It has pledged to expand its reserves within the next five to eight years. CNPC is the parent company of listed firm PetroChina.