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.
Middle horizontal lines represent medians; boxes, the interquartile range; and error bars, 1.5 times the interquartile ranges beyond the 25th and 75th percentiles. Outliers are represented by dots.
