Requirements for a referendum to pass

The Constitution of the Republic of Namibia (adopted in 1992)

Article 132 (3c) If upon the holding of such a referendum the bill containing the proposed repeals and/or amendments is approved by a two-thirds majority of all the votes cast in the referendum, the bill shall be deemed to have been passed in accordance with the provisions of this Constitution, and the President shall deal with it interms of Article 56 hereof. 

2/3 of votes