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.
Densities for males (top) and females (bottom) of less than 20% are not shown. Background colours show the sun angle for an observer at latitude of 74.5°S with contour lines for astronomical twilight (-12°), nautical twilight (-8°), civil twilight (-6°) and sun rise/set (-0.8°). Night time (sun angle below -8°) is grey, while day time (sun angle above -8°) is yellow.
