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.
Threshold maps for all cases. A, Case 15-01. B, Case 15-03. C, Case 15-04. D, Case 15–02. Color code in A applies to all figures. Darker tiles represent lower thresholds. Lighter tiles represent higher thresholds. White tiles represent that a threshold was not measured. Other conventions are the same as in Figure 1.
