The number of radio stations (275) in the U.S. in 1935. By 1941, the number of stations increased to 882. This paralleled a rise in the number of Americans owning radios.

So what?

Often the increase in the number of channels engenders an increased appetite for content within those channels. An increase in Smartphone ownership, for instance, parallels the rise in the number of apps available for use by Smartphone owners.