the folks I get it from hanging with were New Hampshire, Maine and New Brunswick natives. No marbles. No R's either, if at the ends of words. Varies with location how long it takes to get the three words out. Canadians and Mainers right quick, New Hampshirites draw it out.
of course, down here in the Brandywine Valley growing up the equivalent expression was, "Good show, indeed!", or, perhaps, "Settlesworth! Get the Car!" and down in VA, "Damn Yankees" served for most every situation.
