The following information is from the Royal Australian Mint Annual Reports.
In the 2007-2008 Financial Year, the Royal Australian Mint produced 196,685,000 Australian general circulation coins.
In the 2008-2009 Financial Year, the Royal Australian Mint produced 167,600,000 Australian general circulation coins.
The statistics for the 2009-2010 Financial Year are not yet available.
The first exclusively Australian coins were issued for circulation in 1910. Any coins circulated in Australia prior to 1910 were British coins. Occasionally there were coins from other countries suitably restruck for circulation in Australia.
I do not believe there is a finite lifespan for Australian coins. They stay in circulation until they are damaged or too worn to be identified easily. There are still many of the first issue of Australian 1966 decimal coins in circulation.
Australian coins have not changed since last year. General circulation coins are - 5, 10, 20 and 50 cents, and $1 and $2 coins.
Prior to 1933, New Zealand used mainly British coins and a some Australian coins.
The first Australian coins to be put into circulation were the Threepence, Sixpence, Shilling and Florin in 1910.
Silvery coloured Australian coins in general circulation are the 5, 10, 20 and 50 cent coins. Their composition is 75% copper and 25% nickel. There is no silver in any circulating Australian coin.
Coins returned to the Royal Australian Mint (RAM) because they are worn, damaged or mutilated, or coins that were minted surplus to requirements, are melted down and recycled into new coins if possible or applicable. The RAM does not deal directly with the public. Worn, damaged or mutilated coins should be deposited with a bank. The Bank will then make the necessary arrangements to get the coins back to the mint and out of circulation. Coins that are so badly mutilated or damaged that they cannot be identified will not be accepted.
If you refer to the Australian One and Two Dollar general circulation coins, there is no gold in them, they are made from 92% copper, 6% aluminium, 2% nickel giving them a gold appearance. There are no precious metals in any Australian general circulation coins. Australian non-circulating gold coins which are released annually for investors and collectors, contain 99.99% gold.
The Australian 1 cent coin, along with the 2, 5, 10, 20 and 50 cent coins, were first issued on the 14th of February, 1966 for the introduction of Australia's decimal currency. The last Australian 1 cent coins were issued for circulation in 1990 and they were progressively withdrawn from circulation in 1994.
Such a coin does not exist. The last Australian 1 cent coins were issued for circulation in 1990. They were progressively withdrawn from circulation in 1992.
The Royal Australian Mint advises that from 1984 to 2009, approximately 754.246 million Australian One Dollar coins have been minted for general circulation.
Australia's current currency is made up of the 5, 10, 20, 50 and 100 Dollar notes. General circulation coins include the 5, 10, 20 and 50 cent coins and the 1 and 2 Dollar coins. The Australian 1 and 2 cent coins were withdrawn from circulation in 1992.