The politics of Zambia takes place in a framework of a presidential representative democratic republic, whereby the president of Zambia is head of state, head of government and leader of a multi-party system. Executive power is exercised by the government, while legislative power is vested in both the government and parliament. Formerly Northern Rhodesia, Zambia became a republic immediately upon attaining independence in October 1964. Whilst Zambia has since functioned as a democracy from independence it soon became a one-party state for 19 years from 8 December 1972 until multi-party democracy was re-introduced on 4 December 1990 which led to multi-party elections on 1 November 1991. Since then, Zambia has been a relatively stable democracy having consistently peacefully transferred power between four political parties (UNIP, MMD, PF and UPND) and has since 1991 held nine presidential elections, of which seven were general elections. The Economist Intelligence Unit (EIU) rated Zambia as a hybrid regime in 2020. The EIU has also consistently put Zambia among the top ten most democratic African countries, ranking it 8th in Africa and 99th in the world as of 2018 (167 states). This is also while Freedom House ranks Zambia as ‘Partly Free’, with a score of 52/100 (0 least free and 100 mostly free) as of 2021. Government and constitution The constitution promulgated on August 25, 1973, abrogated the original 1964 constitution. The new constitution and the national elections that followed in December 1973 were the final steps in achieving what was called a "one-party participatory democracy". The 1973 constitution provided for a strong president and a unicameral National Assembly. National policy was formulated by the Central Committee of the United National Independence Party (UNIP), the sole legal party in Zambia. The cabinet executed the central committee's policy. In accordance with the intention to formalise UNIP supremacy in the new system, the constitution stipulated that the sole candidate in elections for the office of president was the person selected to be the president of UNIP by the party's general conference. The second-ranking person in the Zambian hierarchy was UNIP's secretary-general. In December 1990, at the end of a tumultuous year that included riots in the capital and an attempted coup, President Kaunda signed legislation ending UNIP's monopoly on power. In response to growing popular demand for multiparty democracy, and after lengthy, difficult negotiations between the Kaunda government and opposition groups, Zambia enacted a new constitution