3 Million

The number of radios (3,000,000) in the U.S. in 1924. Twelve years later the number increased to 30,000,000.

So what?

New communication channels — like radio in 1924 — are often rapidly embraced by the public. This, in turn, creates demand for professionals in the field, like radio announcers, technicians, and writers. Something similar is going on today with social media.