Large districts would be attributed an extra number of notional voters, equal to 1.5% the area of the district in square kilometres, for the purposes of this calculation. This Large District Allowance will permit large rural districts to have many fewer voters than the average district enrolment. The Office of the Electoral Distribution Commissioners gives the following example: Central Kimberley-Pilbara district has 12601 electors and an area of 600038 square kilometres. The average district enrolment for WA is 21343. Central Kimberley-Pilbara thus obtains 9000 notional extra electors, bringing its notional total to 21601, which is acceptably close to the average district enrolment. A modified form of malapportionment was, however, retained for the Legislative Council, the state upper house. Rural areas are still slightly overrepresented, with as much as six times the voting power of Perth on paper. According to ABC election analyst Antony Green, the rural weighting in the Legislative Council is still significant enough that a Liberal state premier has no choice but to include the National Party in his government, even if the Liberals theoretically have enough seats in the Legislative Assembly to govern alone. This situation remained until November 2021, when the Electoral Legislation Amendment (Electoral Equality) Bill 2021 was passed, replacing the malapportioned regions with a single state-wide electorate of 37 members. GVTs were also replaced by optional preferential voting. The changes will take effect in the 2025 state election. The Parliament The Parliament of Australia is a bicameral (two-house) parliament. It combines some of the features of the Parliament of the United Kingdom with some features of the United States Congress. This is because the authors of the Australian Constitution had two objectives: to reproduce as faithfully as possible the Westminster system of parliamentary government, while creating a federation in which there would be a division of powers between the national government and the states, regulated by a written constitution. In structure, the Australian Parliament resembles the United States Congress. There is a House of Representatives elected from single-member constituencies of approximately equal population, and there is a Senate consisting of an equal number of senators from each state, regardless of population (since 1975 there have also been senators representing the territories). But in function, the Australian Parliament follows the Westminster system. The Prime Minister holds office because they can command the support of the majority of the House of Representatives, and must resign or