Such arrangements are common in other countries, and not unknown in England and Wales.

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Overall there are a lot of unknown costs to countries, companies and citizens if a country changes currencies.

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May God have mercy on our two countries as we face the unknown.

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Not just America but parts of Europe, China, Argentina, Brazil, Mexico, Canada and several African countries, among others, sit atop as yet unknown quantities of gas that could transform their energy outlook.

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He said developing countries have felt it is more important to deal with "known risks" than unknown risks like smallpox, while industrialised nations have different priorities.

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The league table, based on estimates from the International Diabetes Federation, includes most countries - apart from a few African nations, where often the rate of type 1 incidence is unknown.

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