Cuba's national legislature, the National Assembly of People's Power ("Asamblea Nacional de Poder Popular"), is the supreme organ of power; 609 members serve five-year terms. The assembly meets twice a year; between sessions legislative power is held by the 31 member Council of Ministers. Candidates for the Assembly are approved by public referendum. All Cuban citizens over 16 who have not been convicted of a criminal offense can vote. Article 131 of the Constitution states that voting shall be "through free, equal and secret vote". Article 136 states: "In order for deputies or delegates to be considered elected they must get more than half the number of valid votes cast in the electoral districts".