The Australian Senate is the upper house of the bicameral Parliament of Australia, the lower house being the House of Representatives. The composition and powers of the Senate are established in Chapter I, Part II of the Australian Constitution. There are a total of 76 senators; 12 senators are elected from each state, regardless of population. Each of the two autonomous internal territories (the Australian Capital Territory and the Northern Territory) have two senators. Senators are popularly elected under a single transferable vote system of proportional representation. There is no constitutional requirement for the election of senators to take place at the same time as those for members of the House of Representatives, though the government usually tries to synchronise election dates.