The New Joint Endeavor for Welfare, Education, and Liberation, or New JEWEL Movement (NJM), was a Marxist–Leninist vanguard party in the Caribbean island nation of Grenada that was led by Maurice Bishop.

Established in 1973, the NJM issued its manifesto prior to the granting of independence to Grenada in 1974. The movement took control of the country with a successful bloodless revolution in 1979 and ruled by decree as the People's Revolutionary Government until 1983. In 1983, Bishop was killed by paramilitaries affiliated with hard-liners in his own party. This led to a military government, which was deposed by the US military in a 1983 invasion.
Using the reference information, how many years was the People's Revolutionary Government in control in Grenada, and under what leader?
Maurice Bishop led the People's Revolutionary Government for 4 years in Grenada, between 1979 and 1983.