Travel Information about USA and Washington D.C.

(GMT)12 FEB 2017 PLTC:  Ethnic Map of USA.
The dominant ethnicity group by population in the United States. Almost half of America's population reported to have German Ancestry.
It says 'The third most common ancestry reported are purely Americans' Who are those pure Americans?
http://usandcanadacultureregion.weebly.com/ethnicity.html