Figure 2. A quantitative summary of distribution of included papers. Analysis of search results were conducted to demonstrate (A) country of publication, (B) publication type, and (C) publication year.
Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.