Profile America — Saturday, February 22nd. The history of radio and the presidency seems to center entirely on Franklin Roosevelt's famous "fireside chats" beginning in 1933 in the depths of the Depression. But the first president to address the nation from the White House over the infant broadcast medium was, ironically, "Silent Cal." President Calvin Coolidge spoke to a coast-to-coast audience on this date in 1924 on the occasion of George Washington's birthday. His words were carried over just 42 stations. That year, there were 530 radio stations in the country, broadcasting to just 1.25 million households. Today, there are over 6,300 radio stations employing over 100,000 people, and 114 million or 99 percent of U.S. households have radios. Profile America is in its 17th year as a Public Service of the U.S. Census Bureau.
Library of Congress, America's Story
Historical Statistics of the United States: Colonial Times to 1970, p. 796
http://factfinder2.census.gov/faces/tableservices/jsf/pages/productview.xhtml?pid=ECN_2007_US_51A1&prodType=table NAICS 515112