Reserve currency tipping point hypothesis

Ok, here is another crazy thought. The only thing keeping the US dollar from collapsing right now is the fact that it is the global currency and no replacement is in sight.

But what if there is a replacement?  What if the combined currencies from my hypothetical South Pacific Confederation become the replacement?  So my hypothesis is that if the combined South Pacific currencies are used more than the US dollar, then that will be a tipping point causing abandonment of faith in the dollar, and then hyperinflation of the dollar into oblivion.

What if the South Pacific currencies (as well as the yuan) increase by 10% per year, and the US dollar decreases by 2/3 of that (with the other 1/3 decrease coming from the use of the euro, yen and pound).  When would the tipping point occur?

As a starting point, here are the daily share of traded currencies (from Wikipedia):
US dollar 84.9%
Euro 39.1%
Japanese yen 19.0%
UK pound 12.9%
Australian dollar 7.6%
Hong Kong dollar 2.4%
New Zealand dollar 1.6%
South Korean won 1.5%
Singapore dollar 1.4%

I calculate this will occur in 2027.  At that point 61% of all Forex transactions will use the Australian dollar, Hong Kong dollar, New Zealand dollar, Singapore dollar, South Korean won, or Chinese yuan. The US dollar will be used in only 54% of transactions.  The euro, yen and pound combined will be used in 56% of transactions, and other currencies will be used in 30% of transactions.  (The total equals 200% because we are looking at both sides of the currency pair).

At that point the US dollar will no longer be an essential part of the world economy.  It will still be a major player, but our unlimited license to print money card will be revoked.

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Update: The trend is definitely happening, but it is a lot slower than I stated above.  Better numbers are that the South Pacific currencies will increase by 3.2% per year, with the US dollar decreasing by 2/3 of that.  Using these figures, the tipping point will occur in 2051, when the US dollar will account for only 57.1% of all transactions, and the South Pacific currencies accounting for 57.5%.

See http://www.bis.org/publ/rpfxf10t.htm for data on currencies.

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Upon further reflection, I don't think this is a valid way of looking at things.  A basket of currencies will not be a replacement for the dollar.  For there to be a threat, there needs to be a single currency that is credible enough to be a replacement.  And I don't think the Australian dollar will ever be that currency.  It is an interesting thought experiment though.