Bae, Suk Won http://orcid.org/0000-0002-2250-9604
Article History
Received: 2 September 2020
Accepted: 27 December 2020
First Online: 12 January 2021
Ethics approval and consent to participate
: The data obtained the National Statistical Office’s national approval statistics qualification (Approval number: 439001).
: Not applicable.
: The authors declare that they have no competing interests.