1. College of Mathematics and Statistics, Chongqing Technology and Business University, Chongqing, P.R. China
2. Chongqing Key Laboratory of Social Economy and Applied Statistics, Chongqing Technology and Business University, Chongqing, P.R. China
3. School of Statistics, Beijing Normal University, Beijing, P.R. China
4. Institute of National Accounts, Beijing Normal University, Beijing, P.R. China