Once upon a time…

…a goodly chunk of the world was Pink - we used to have an "Empire"; hoping that Link works for those who don't know &/or have forgotten.
       I really did not sort my coins properly - SO - I dug out and sorted some of the "evidence"; this being, possibly the first, haven't checked, but probably the most distant.
       AHA memory hath struck - I did an Aussie half crown not long ago another - SO - this must be after they decided to "dollarise" their currency? 
       HAD to check, even though it was obvious:-
"On 14 February 1966, Australians woke to a brand-new currency.  The decision to change from the Australian pound (with its awkward shillings and pence) to a decimal currency – the Australian dollar – was a pragmatic, economic one."