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.
Sample selection flowchart. aThe percentage was calculated based on the number of participants eligible in survey 8 (2016) (n = 10,716). bThe percentage was calculated based on the number of participants completed survey 8 (n = 8,622). cThe percentage was calculated based on the number of participants responded to both survey 8 and survey 9 (2019) (n = 7,164).
