Guo, Yu
Wang, Tian
Ge, Tingshuai
Jiang, Quanbao
Article History
Received: 18 April 2022
Accepted: 26 August 2022
First Online: 1 October 2022
Declarations
:
: In this study we used only tabulated data from China’s population census without any individual information. No ethics approval was required. All methods were carried out in accordance with relevant guidelines and regulations.
: Not applicable.
: The authors declare that they have no competing interests.