Fig. 1.
Study population selection criteria, National Survey of Family Growth, 2006-2017
EC = emergency contraception.
aQuestion introduced in year 2 of 2006-2010 survey.
bQuestion introduced in year 3 of 2006-2010 survey.
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.