Norfolk Island:

Disagreements over the island's relationship with Australia were put in sharper relief by a 2006 review undertaken by the Australian government. Under the more radical of two models proposed in the review, the island's legislative assembly would have been reduced to the status of a local council. However, in December 2006, citing the "significant disruption" that changes to the governance would impose on the island's economy, the Australian government ended the review leaving the existing governance arrangements unaltered.

Please answer a question about this article. If the question is unanswerable, say "unanswerable". When did the European government end their review on Norfolk Island?
unanswerable