It is officially the Commonwealth of Australia, is a country comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands. It is the world's sixth-largest country by total area. Neighboring countries include Indonesia, East Timor and Papua New Guinea to the north; the Solomon Islands and Vanuatu to the north-east; and New Zealand to the south-east.
On 1 January 1901, the six colonies federated, forming the Commonwealth of Australia. Since Federation, Australia has maintained a stable liberal democratic political system that functions as a federal parliamentary democracy and constitutional monarchy comprising six states and several territories. The population of 23.6 million is highly urbanized and heavily concentrated in the eastern states and on the coast.
Australia is a developed country and one of the wealthiest in the world, with the world's 12th-largest economy. In 2012 Australia had the world's fifth-highest per capita income. With the second-highest human development index globally, Australia ranks highly in many international comparisons of national performance, such as quality of life, health, education, economic freedom, and the protection of civil liberties and political rights.