1996 The Thirtieth Anniversary of Decimal Currency in Australia, 1966-1996 Proof $1 Coin. On the 14th of February 1996 Australia celebrated 30 years of decimal currency. To commemorate this significant date, the Royal Australian Mint has issued a special mintage proof $1 coin. Produced to exacting proof quality standards, the mintage of this one ounce fine silver commemorative coin is limited by the demand of the Royal Australian Mint's collectors. Mintage 19,927. Certificate of Authenticity is included with this coin numbered 11,827.