True, the majority of the population of this country can be classified in the “white” ethnic group, but a glance at this map would suggest that they were the overwhelming majority, when they are not.

However, the predominance of whites in rural and low-population areas, and the heavy concentration of ethnics in urban areas, gives a misleading picture when mapped this way. It makes it look like the country is mostly white, with a few isolated pockets here and there of non-whites. This is not exactly the case, and the misperception is not a flaw of the data, but a shortcoming of the display method. The blue dots are easiest seen out in the tules, but most Americans (82%) live in the cities where the dots merge.

The key figures to keep in mind (from the 2010 census):

Non-Hispanic white and European – 63.7%
Non-Hispanic black – 12.2%
Hispanic – 16.4%
Asian – 4.8%
Native American – 0.9%

http://en.wikipedia.org/wiki/Demographics_of_the_United_States#Race_and_ethnicity