I'm part German...
Almost all Americans are. German is the single largest ancestry group in the US. And that is with the people who admit it... During WWII many German families edited their own history from German to say they were some other... (Italian, etc.). Some 28% currently admit to German... It is very likely to be far higher than that. With the way ancestries are mixed in the US it is unlikely people do not have some German ancestry (of course some do not, but the chances of YOU being one of them is unlikely at best).