Here’s the Arbitron/Edison study on the JACK format, here regrettably referred to as “Adult Hits” (If ever there was a label aimed at taking all the flavor out of a format, that label would be “Adult Hits.” How about “Cornucopi-AC”?).
Very little here I didn’t already know, but maybe you’ll find something useful.
Low TSL, high Cume.
Sounds like another little format called CHR.
And that one is in every market in America.