Anecdata: a few years ago I did a road trip through NV, UT, and CO, and for large swathes of that trip, the only radio station that wasn't glassy-eyed christian pap ("if we make 20k donations, it can ONLY by god's will!" and similar) was NPR. If I lived in the area, it would be the only sane choice for radio...
~30 million users per week would put NPR on par with some of the social networks. Amazing feat by NPR if that number is legit.