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.
The solid lines are the regression lines for the data points from rounds 10 to 26; the dashed lines are the regression lines for the data points from rounds 28 to 44.
