Very first signs of a discussion along these lines can be found in the FOMC minutes of the November 13, 1996 meeting, a few weeks before Chairman Greenspan made his famous “irrational exuberance” speech.
Measured per hour, labour productivity growth averaged 4.7% in the 1960s and 1970s, 2.2% in the 1980s and 1990s and around 1.3% at the beginning of this century.