convened the Constituent Cortes (the Spanish Parliament, in its capacity as a constitutional assembly) for the purpose of drafting and approving the constitution of 1978. After a national referendum on 6 December 1978, 88% of voters approved of the new constitution – a culmination of the Spanish transition to democracy. As a result, Spain is now composed of 17 autonomous communities and two autonomous cities with varying degrees of autonomy thanks to its Constitution, which nevertheless explicitly states the indivisible unity of the Spanish nation. The constitution also specifies that Spain has no state religion and that all are free to practice and believe as they wish. The Spanish administration approved the Gender Equality Act in 2007 aimed at furthering equality between genders in Spanish political and economic life. According to Inter-Parliamentary Union data as of 1 September 2018, 137 of the 350 members of the Congress were women (39.1%), while in the Senate, there were 101 women out of 266 (39.9%), placing Spain 16th on their list of countries ranked by proportion of women in the lower (or single) House. The Gender Empowerment Measure of Spain in the United Nations Human Development Report is 0.794, 12th in the world. Government Spain is a constitutional monarchy, with a hereditary monarch and a bicameral parliament, the Cortes Generales (). The legislative branch is made up of the Congress of Deputies (Congreso de los Diputados), a lower house with 350 members, elected by popular vote on block lists by proportional representation to serve four-year terms, and the Senate (Senado), an upper house with 259 seats of which 208 are directly elected by popular vote, using a limited voting method, and the other 51 appointed by the regional legislatures to also serve four-year terms. The executive branch consists of a Council of Ministers presided over by the Prime Minister, who is nominated as candidate by the monarch after holding consultations with representatives from the different parliamentary groups, voted in by the members of the lower house during an investiture session and then formally appointed by the monarch. Head of State (King) Felipe VI, since 19 June 2014 Government Prime Minister (head of government) or "President of the Government" (Presidente del Gobierno): Pedro Sánchez Pérez-Castejón, elected 1 June 2018. Deputy prime ministers (designated by the Prime Minister): Currently Nadia Calviño Santamaría (1st), Yolanda Díaz Pérez (2nd), Teresa Ribera Rodríguez (3rd). Ministers (designated by the