The Parliament of Australia, officially "The Parliament of the Commonwealth" but commonly referred to as the Commonwealth Parliament or the Federal Parliament, is the legislative branch of the government of Australia. It consists of three elements: the Queen, the Senate and the House of Representatives. The Queen is represented by the Governor-General. The combination of two elected houses, in which the members of the Senate represent the six States and the two major self-governing Territories while the members of the House represent constituencies according to population, is modelled on the United States Congress. Through both houses, however, there is a fused executive, drawn from the Westminster System.The upper house, the Senate, consists of 76 members: twelve for each state, and two each for the Northern Territory and the Australian Capital Territory. Senators are elected using a form of proportional voting. The lower house, the House of Representatives, currently consists of 150 members, who represent districts known as electoral divisions (commonly referred to as "electorates" or "seats"). The number of members is not fixed, but can vary with boundary changes resulting from electoral redistributions, which are required on a regular basis. The most recent overall increase in the size of the House, which came into effect at the 1984 election, increased the number of members from 125 to 148. It reduced to 147 at the 1993 election, returned to 148 at the 1996 election, and has been 150 since the 2001 election. Each division elects one member using compulsory preferential voting. The two Houses meet in separate chambers of Parliament House on Capital Hill in Canberra, Australian Capital Territory.