China statistical yearbooks database http://tongji.oversea.cnki.net/oversea/engnavi/navidefault.aspx (English) ; Chinese title is 中国经济社会发展统计数据库 (Zhongguo jing ji she hui fa zhan tong ji shu ju ku). http://tongji.oversea.cnki.net/chn/navi/navidefault.aspx (For Chinese interface)