Where are the Americans?

A Somali arrives in Minneapolis as a new immigrant to the United States. He stops the first person he sees walking down the street and says, 
 
"Thank you Mr. American for letting me in this country, and giving me housing, food stamps, free medical care and free education!"  But the passer-by says "You are mistaken, I am Mexican". 
 
The man goes on and encounters another passer-by and says, "Thank you for having such a beautiful country here in America!" The person says "I no American, I Vietnamese." 
 
The new arrival walks further, and the next person he sees he stops, shakes his hand and says "Thank you for the wonderful America!" That person puts up his hand and says "I am from Middle East, I am not an American!" 
 
He finally sees a nice lady and asks suspiciously, "Are you an American?" She says, "No, I am from Russia!" So he is puzzled, and asks her, "Where are all the Americans?" The Russian lady looks at her watch, shrugs, and says... "Probably at work!"