Organisation Name of house(s) House level Term (years) Voting system Seats Population per seat GDP per seat (million USD) European Union European Parliament[1] Unicameral 5 Open and closed list proportional representation, and single transferable vote (in Ireland) 751 667,761 20,983 African Union Pan-African Parliament Unicameral 5 indirect (appointed by 47 of 53 national legislatures) 265 3,974,098.11 14.180 Central American Integration System Central American Parliament Unicameral Depends per country. direct, proportional 120 426,274.46 2,651.175 Mercosur Mercosur Parliament Unicameral 5 direct, indirect (depends per country) proportional 122 1,588,889 16.228 Community of Latin American and Caribbean States Latin American Parliament Unicameral 5 direct 276 ~ ~ Arab League Arab Parliament Unicameral 68