Measuring radio's penetration in 1936

Here's a scan of a 1936 report on the state of radio penetration, commissioned by CBS as a sales tool to convince advertisers to shift their spending to broadcast. Bary sez, "The book and pamphlet present ownership, listenership broken down by age, sex, income and other demographics. In addition it includes number of tubes replaced and regional maps of the US."
As such, this booklet completes the CBS study: RADIO IN 1936. The two volumes combine into a reference service for any basic consideration of how to sell more merchandise to the people with money enough to pay..."

A preliminary examination of this project indicated that in order to obtain a complete answer, it would probably be necessary to make a very extensive field survey, which would have meant delay and heavy expense. The Committee therefore decided that the interests of all parties concerned would be best served by making the best possible estimate, based on existing figures and on additional data that could be gathered in a reasonable length of time.

Radio in 1936 (Thanks, Bary, via Submitterator!)