Apportionment by country describes the practices used in various democratic countries around the world for partitioning seats in the parliament among districts or parties. See apportionment (politics) for the general principles and issues related to apportionment.
Australia
The Australian House of Representatives consists of 151 single-member seats, referred to as constituencies, electorates, or electoral divisions. Seats are apportioned between the states and territories according to a formula based on population, but each state is constitutionally guaranteed a minimum of five seats. Tasmania is the only state affected by this clause; as such, while electorates in other states average around 105,000 to 125,000 voters, Tasmania's electorates average around 73,000 to 80,000 voters. Federal electoral boundaries are regulated by the Australian Electoral Commission (AEC), which regularly redistributes seats and boundaries to reflect changes in population. Since 1974, federal electorates within each state may not vary in population by more than 10%, largely preventing malapportionment. The Constitution of Australia states that the size of the House of Representatives must be, “as nearly as practicable”, twice the number of senators. Accordingly, the House has periodically been expanded along with the Senate, from 76 seats in 1901 to its present size of 151 seats.
In the Australian Senate, each state is represented by 12 senators. Tasmania, with a population of 534,000, elects the same number of senators as New South Wales, with a population of almost 8.1 million. Equal representation of the states in the Senate is written into the Constitution, intended to protect the interests of smaller states. Amending the Constitution to repeal the equal representation can only be done through a national referendum. However, the specific number of Senate seats allocated to the States is not constitutionally defined, and can be modified by legislation. Starting from six seats for each state in 1901, it was increased to 10 in 1948, then to 12 in 1984. Territories are not guaranteed Senate representation by the Constitution, and were unrepresented until 1975, when legislation was passed granting each territory two seats in the Senate. The Senate's present size is 76 seats.
There has been malapportionment of electorates in both the federal and state parliaments in the past, typically in the form of rural areas receiving disproportionately more seats than urban areas. Supporters of these arrangements claimed Australia's urban population dominates the countryside, and that these practices gave fair representation to country people. Such systems were in place in Queensland from 1949 to 1991, Western Australia from 1907 to 2007, and South Australia from 1856 to 1968. In Queensland, the state was divided into four electoral regions between which constituencies were distributed, with rural areas receiving disproportionately high representation. In WA, the area around Perth was limited to a maximum of 60% of seats, despite containing a much larger share of the population. In SA, the constitution stated that rural areas must have twice as many seats as Adelaide and its suburbs, despite the large majority of the population residing in the city. These systems allowed the Country Party of Queensland (later named the National Party) in Queensland and the Liberal and Country League in SA to retain majorities in Parliament despite losing the popular vote, sometimes by a substantial margin. In SA, a less significant system of malapportionment remained until 1991, when it was repealed by referendum. (See: Australian electoral system#Gerrymandering and malapportionment.)
Canada
In Canada, each federal electoral district ("riding") is represented by one Member of Parliament (MP). Ridings are based on population, but each territory is also given an MP; so Nunavut receives one MP even though its population in 2006 was only 29,474.
Certain provisions in the Constitution and law (the "grandfather clause" and the "senatorial clause") guarantee that provinces cannot have fewer MPs than they had in 1982. The apportionment method is to grant one MP to each territory, and allocate 279 other MPs according to population among the 10 provinces. After doing so, the provinces with slower historical population growth since joining the Confederation receive extra ridings so as not to lose MPs. After the 1991 Census, 19 extra ridings were created, making a total of 301. After the 2001 Census, seven more ridings were created, making a total of 308.