Bolivia elects on national level a head of state – the president – and a legislature. The president and the vice-president are elected for a five-year term by the people. The National Congress ("Congreso Nacional") has two chambers. The Chamber of Deputies ("Cámara de Diputados") has 130 members, elected for a five-year term using the Additional Member System, and in the case of seven indigenous seats by "usos y costumbres". The Chamber of Senators ("Cámara de Senadores") has 36 members: each of the country's nine departments returns four senators allocated proportionally.