The Australian twenty-cent coin (Quinter) of the Australian decimal currency system was issued with conversion to decimal currency on 14 February 1966, replacing the florin which was worth two shillings, a tenth of a pound. To date, four different obverse face designs have been used: from 1966 to 1984, the head of Queen Elizabeth II by Arnold Machin; from 1985 to 1998, the head by Raphael Maklouf; from 1999 to 2019, the head by Ian Rank-Broadley; and since 2019, the head by Jody Clark. The obverse has the inscription AUSTRALIA and the year-of-issue on the right hand side, and ELIZABETH II on the left hand side. From 1966 to 1994, the design for the reverse face was Stuart Devlin's platypus. With the exception of commemorative issues, it continues to be the standard design for the reverse face. The United Nations 20c was the first commemorative 20c coin issued for circulation in 1995. Commemorative designs had been issued for circulation previously in other denominations. 20c coins are legal tender for amounts not exceeding $5 for any payment of a debt. Commemorative coins There have been various commemorative issues with following reverse face designs: 1995: 50th Anniversary of the United Nations (with the UN emblem). 2001: Commemoration for Sir Donald Bradman (1908–2001). 2001: Centenary of Australian Federation: a set of nine coins; six for the states, two for the territories and one for Norfolk Island. The designs were made by students from each of the areas. 2003: Commemorating Australia's Volunteers. "AUSTRALIA'S VOLUNTEERS - MAKING A DIFFERENCE" 2005: 60 years since the end of the Second World War, with WORLD WAR 1939-1945 COMING HOME. The design was inspired by a photo from the Australian War Memorial collection. 2010: Centenary of the Australian Taxation Office. 2011: Wedding of HRH Prince William and Catherine Middleton: Duke and Duchess of Cambridge. 2011: Centenary of International Women's Day. 2011: 10th anniversary of the International Year of Volunteers. (IYV +10) 2013: Centenary of Canberra 2016: 50th Anniversary of decimal currency - unusually for Australian coins, this is a commemorative obverse; the reverse is as normal. Varieties Excepting commemorative varieties, there have been a number of varieties of regular issue coins identified by collectors, on both the obverse and reverse faces. The first of these seen is a highly prized variety of the 1966 issue, with a "wave" on the top of the bottom stroke of the 2 in