Couldn't say. My friend and I are of Scandianvian extraction and communities in Washington State (Dad's Irish family was scattered around back east), and we lived near the Canadian border. Perhaps the influence of the Canadian/British radio or tv had something to do with this saying, perhaps the Scandinavian background harbored it. My ex used to rag me about some of my Scandihoovian sayings. "You betcha" always seemed to get a response.

SRS