How many spinoffs did the TV series “Happy Days” (ABC, 1974-84) generate?

The TV series “Happy Days” (ABC, 1974-84) generated three spinoffs:

“Laverne and Shirley” (ABC, 1976-83) “Mork and Mindy” (ABC, 1978-82) “Joanie Loves Chachi” (ABC, 1982-83).