In 2017 the proportion of couples marrying in a civil ceremony in Victoria was 77.3%; the other 22.7% were married in a religious ceremony. The government predicts that nearly a quarter of Victorians will be aged over 60 by 2021. The 2016 census revealed that Australian median age has crept upward from 35 to 37 since 2001, which reflects the population growth peak of 1969–72. In 2017, Victoria recorded a TFR of 1.724. In 2011–2012 there were 173 homicides. Victoria has a parliamentary form of government based on the Westminster System. Legislative power resides in the Parliament consisting of the Governor (the representative of the Queen), the executive (the Government), and two legislative chambers. The Parliament of Victoria consists of the lower house Legislative Assembly, the upper house Legislative Council and the Queen of Australia. Eighty-eight members of the Legislative Assembly are elected to four-year terms from single-member electorates. In November 2006, the Victorian Legislative Council elections were held under a new multi-member proportional representation system. The State of Victoria was divided into eight electorates with each electorate represented by five representatives elected by Single Transferable Vote. The total number of upper house members was reduced from 44 to 40 and their term of office is now the same as the lower house members—four years. Elections for the Victorian Parliament are now fixed and occur in November every four years. Prior to the 2006 election, the Legislative Council consisted of 44 members elected to eight-year terms from 22 two-member electorates. The Premier of Victoria is the leader of the political party or coalition with the most seats in the Legislative Assembly. The Premier is the public face of government and, with cabinet, sets the legislative and political agenda. Cabinet consists of representatives elected to either house of parliament. It is responsible for managing areas of government that are not exclusively vested in the Commonwealth, by the Australian Constitution, such as education, health and law enforcement. The current Premier of Victoria is Daniel Andrews. Executive authority is vested in the Governor of Victoria who represents and is appointed by Queen Elizabeth II. The post is usually filled by a retired prominent Victorian. The governor acts on the advice of the premier and cabinet. The current Governor of Victoria is Linda Dessau. Victoria has a written constitution enacted in 1975, but based on the 1855 colonial constitution, passed by the United Kingdom Parliament as the "Victoria Constitution Act 1855", which establishes the Parliament as the state's law-making body for matters coming under state responsibility. The Victorian Constitution can be amended by the Parliament of Victoria, except for certain "entrenched" provisions that require either an absolute majority in both houses, a three-fifths majority in both houses, or the approval of the Victorian people in a referendum, depending on the provision.