Funding for this research was provided by:
National Natural Science Foundation of China (12071308)
National Natural Science Foundation of China (11601349)
Scientific research planned project of National Bureau of Statistics of China (2017LZ15)
National Natural Science Foundation of China (11501095, 11631003, 11690012)
National Key Research and Development Program of China (2020YFA0714102)
Article History
Accepted: 16 August 2021
First Online: 11 September 2021