Also, for whatever reason (I don't know much about contemporary urban radio, its music styles, and demographics), WJMN's numbers have declined quite a bit over the past couple of decades from its heyday in the '90s and early 2000's when it was usually in the top five. Back then it was usually "Kiss-108" on top with the CHR pop, and sister station "Jammin'" a close second with CHR rhythmic and hip-hop.
WJMN may still bill well and provide iHeart a good "package" with Kiss for the young CHR audience, but it hasn't even been in the top ten for at least a few years. WKAF (now also a sister station to Kiss and Jammin'), even with its currently uptrending ratings, couldn't have touched the numbers WJMN had some years ago.
I don't know why WJMN's numbers have dropped in recent years, but noticing that WBQT (somewhat more adult oriented) has been beating them lately, and upcoming little WKAF (much more adult oriented) also just bested them, I'm going to guess that the younger audience is now getting much of their music from non-broadcast digital sources rather than radio.