As far as your work goes, do they tune into a local station (like a Top 40, or anything like that), or do they have their own in-house radio broadcast like some places do?
Either way, I have never, ever, not once in my entire life, ever heard a Muppet song on the radio, and the closest thing to it that I have was, years and years ago, a cover of "Sing" was played on the radio, and pretty much completely at random . . . I don't even remember who sang the cover, I just found it odd.