The question of how to put an economic value on increased longevity is addressed in a collection of articles by leading economists published in May.

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The old milk crates I used to keep my record albums in provide more social value than an iTunes music collection.

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Six of the pieces were owned by Richard Neumann, an Austrian Jew who sold off his collection at a fraction of its value in order to leave France.

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She estimates that her collection of 30 pieces has increased in value by about 40% in the last two years.

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Two dealers who know the collection say it's tripled and possibly quadrupled in value in the last decade.

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He cites the example of one of the bank notes in his collection, a 1896 US note with a face value of two silver dollars.

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In a report, it said supporting more efficient tax collection represented "excellent value" for UK taxpayers.

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Its collection of hot stocks, among them Google, Apple and Salesforce.com, has tripled in value since its 2008 low.

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