From Wikipedia:
Little House on the Prairie is an American Western dramatic television program, starring Michael Landon and Melissa Gilbert, about a family living on a farm in Minnesota in the 1870s and 1880s. The show was a loose adaptation of Laura Ingalls Wilder's best-selling series of Little House books. It aired on the NBC network from September 11, 1974, to May 10, 1982. During the 1982-83 television season, with the departure of Michael Landon, the series was broadcast with the new title Little House: A New Beginning. The series itself was preceded by a two-hour pilot movie that first aired on March 30, 1974.
Melissa Gilbert appeared in the majority of Little House episodes, and stayed throughout the entire run. She was absent for thirteen episodes, for a total of 190/203 episodes. Michael Landon appeared in every episode except four for the first eight seasons, then departed from the cast (when the show was retooled as Little House: A New Beginning), for a total of 179/203 episodes.
