A Number Worth Noting

15,440

The number of licensed AM and FM radio stations across the U.S. as of Aug. 20, the 95th anniversary of the first broadcast by a federally licensed station -- 8MK in Detroit, now WJJ -- in 1920. That October, Pittsburgh's KDKA began broadcasting, and by 1922 the nation had 30 stations. A year later, it had 556.

Source: Profile America, U.S. Census Bureau