It's polling. From Kathryn Jean Lopez:
The concept that there is even polling — he has a national approval rating
— on Rush Limbaugh seems worth reflecting upon. He’s an unrivaled
success in broadcasting and, thus, culture. That’s why they poll on him
— wanting a low number (which media coverage of him over the years all
but guarantees) to cite to scare people on the Right away from him.
She's on to them.