Your saying that every 100 times this tournament is played, Australia only whitewash once?
If these teams were perfectly matched, to a 50 50 expected win loss ratio, the odds of an Australian whitewash would be 1 for every 128 times. (.78 out of 100)
If we say Australia 60 40... it becomes 7 in every 250 which is roughly 3 in 100.
Now a more likely 75 25 ratio (IMO) yields 13.3 from 100.
And a 90 10 ratio shows or 47.8 out of a 100.
A tempting bet if there ever was one, statistically speaking of course.