Here is an interesting tidbit:
The average US radio station bills around $800,000 a year.
Here is the average gross sales of individual stores of some of the best known fast food establishments:

So, the average McDonald's has revenue of $3,420,000 which is about four times as much as the average radio station.
Then take into consideration that just under 700 stations in the US billed more than that McDonald's $3.42 million last year, and that is out of about 10,800 commercial stations that are not translators. And those six hundred or so stations make up well over ½ of all radio station revenue.
The average US radio station bills around $800,000 a year.
Here is the average gross sales of individual stores of some of the best known fast food establishments:

So, the average McDonald's has revenue of $3,420,000 which is about four times as much as the average radio station.
Then take into consideration that just under 700 stations in the US billed more than that McDonald's $3.42 million last year, and that is out of about 10,800 commercial stations that are not translators. And those six hundred or so stations make up well over ½ of all radio station revenue.