In Australian and New Zealand business writing, the order is: day (optional), month, year—with no punctuation.
(Friday) 17 April 2009
The media and the US reverse the order, i.e. April 17, 2009.
Dates as numerals
When writing dates as numerals, the conventional sequence in Australia and New Zealand is day, month, year separated by forward slashes or full stops.
20.01.05 or 20/01/05
Some organisations give the century as well as the year.
20.01.1950 or 20/01/1950
When you are referring to a year span within the one decade or within the same century, you don’t need to repeat the century figures.
When referring to decades in the plural, you don’t need an apostrophe.
Fashions were amazing in the 1970s.
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