Peter M,
Sorry but I think the figures you have quoted are inaccurate (exchange rate calculations?).
According to the DWP, Australian defence expenditure for the 2017-18 financial year is approx A$34.2B, which at the current exchange rate, is USD$27.25B.
From what I can find, UK expenditure this year (in UK Pounds) is 48B, which equates to USD$66.22B.
Italian figures are a bit harder to find, but from what I can see Italy is spending approx, in USD, 37.7B
Your figures, above, are suggesting that (in USD), we are just behind the UK and well ahead of Italy, again, sorry, I think that is inaccurate.
Cheers,