We’re now three years and seven shows into the stage-musicals-on-television phenomenon. It’s time to begin drawing conclusions from this continuing experiment.

You’ll recall that NBC began the parade in December 2013 with “The Sound of Music Live!,” which starred Carrie Underwood as Maria. A year later came “Peter Pan Live!,” also on NBC, and last December the network served up “The Wiz Live!” Fox got into the act this year with “Grease: Live!,” “The Passion” and “The Rocky Horror Picture Show,” and on Wednesday night NBC resumed its December tradition with “Hairspray Live!”

[ Review: “Hairspray Live!” Had Power Voices but Still Lacked Power ]

Let’s cut to the chase: “The Wiz” was the best by far. But in terms of ratings, which is what this is really all about, “The Sound of Music” is the king (more than 18 million viewers), fueled no doubt by a curiosity factor, since it was first. “Grease” is second at about 12 million, then and “The Wiz” at 11.5 million. Preliminary numbers for “Hairspray” put it somewhat behind those. But in general the bloom seems to be off the rose, and these musicals are settling into a good-but-not-spectacular ratings zone.