About what fraction of the globe did communists control by 1975?

This circumstance encouraged the North Vietnamese, who propelled a crusade in March 1975 to take the common capital of Ban Me Thuot in the Central Highlands. The South Vietnamese safeguards there battled ineffectively and were overpowered by the North Vietnamese aggressors. At the end of the day, the United States did nothing. President Thieu requested his powers in the Highlands to pull back to more solid positions toward the south.