Harold Rhodes estimated that 250,000 pianos (a quarter of a million) were built during the lifetime of production at CBS from 1965 to 1984. Regarding specific models and eras, all that can be said is that as popularity grew throughout the 1970's, so did demand for the pianos. We have a better idea of how many of the more obscure models were made, such as the Rhodes Home Piano (around 250 built in 1977), the Fender Rhodes Executone (Kenneth Manning states that his is one of 11 total) or the Rhodes Mark IV (one prototype).
Mike Kahrs shared his experience on the assembly line in the late 70's: "CBS was always doing time studies to grind the union for more production. Some cat with a clipboard and stop watch was always lurking about. As I recall, we made about 100 a day. We hated the 88, as we were allowed no more time than the 73 key model. The consensus among the workers was that the 73 was the better made instrument."