Most statistics are published by national or state government agencies. This information is essential for government planning and policy making. In Australia, the Australian Bureau of Statistics is the largest publisher of government statistics.
International organisations such as the United Nations (UN), regularly publish statistics on a number of topics such as health and economics for most countries of the world. Many countries, including Australia, contribute their statistics to international organisations like the Organisation for Economic Co-operation and Development(OECD).
Consulting the websites of these international organisations is very useful when you have to compare conditions in different countries.