 Complete the following phrase:  A non-exhaustive list of recipients includes: Cesar Chavez 1973; Stanley Levison and Kenneth Kaunda 1978; Rosa Parks 1980; Martin Luther King Sr. and Richard Attenborough 1983; Corazon Aquino 1987; Mikhail Gorbachev 1991; and, on April 4, 2018the 50th anniversary 