Query: When did the country of Namibia officially become a country?
Context: The Namibian Constitution adopted in February 1990 incorporated protection for human rights, compensation for state expropriations of private property, an independent judiciary and an executive presidency (the constituent assembly became the national assembly). The country officially became independent on 21 March 1990. Sam Nujoma was sworn in as the first President of Namibia watched by Nelson Mandela (who had been released from prison the previous month) and representatives from 147 countries, including 20 heads of state.