Agricultural Information Institute/Key Laboratory of Big Agri-Data of Ministry of Agriculture and Rural Affairs Chinese Academy of Agricultural Sciences Beijing 100081 P.R.China;
International Statistical Information Center National Bureau of Statistics Beijing 100826 P.R.China;
School of Statistics and Mathematics Central University of Finance and Economics Beijing 100081 P.R.China;
Agricultural Information Institute/Key Laboratory of Big Agri-Data of Ministry of Agriculture and Rural Affairs Chinese Academy of Agricultural Sciences Beijing 100081 P.R.China;
Agricultural Information Institute/Key Laboratory of Big Agri-Data of Ministry of Agriculture and Rural Affairs Chinese Academy of Agricultural Sciences Beijing 100081 P.R.China;