The Economist reported here in February:
German-Americans are America’s largest single ethnic group (if you divide Hispanics into Mexican-Americans, Cuban-Americans, etc). In 2013, according to the Census bureau, 46m Americans claimed German ancestry: more than the number who traced their roots to Ireland (33m) or England (25m). In whole swathes of the northern United States, German-Americans outnumber any other group (see map). Some 41% of the people in Wisconsin are of Teutonic stock.
That figure is down from 51 million before 2009 and from 50 million in 2009, so evidently the German American population is declining by about 1 million per year.
