"The first electric typewriter was built in 1902 by Blickensderfer and was called the Blick Electric. The first electric typewriter which attained some sort of commercial success was the Remington Electric of 1925.
Eventually in 1933 Remington's electric typewriter was taken over by International Business Machines (IBM) under the name Electromatic.
In 1947 the Executive model with proportional spacing was introduced by, followed by the single-element Selectric in 1960 - commonly known today as the "golf-ball" as the type element was easily interchangeable."
From a Swedish page on the history of typewriters:
We had Selectrics when I was in the USMC in the 1980s, but we still used monospaced fonts, mostly because DD-173 message forms had a limit of 69 characters per line.