By the middle of the 1920s the whole of Angola was under control. Slavery had officially ended in Portuguese Africa, but the plantations were worked on a system of paid serfdom by African labour composed of the large majority of ethnic Africans who did not have resources to pay Portuguese taxes and were considered unemployed by the authorities. After World War II and the first decolonization events, this system gradually declined. However, paid forced labor, including labor contracts with forced relocation of people, continued in many regions of Portuguese Africa until it was finally abolished in 1961.