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ParameterUnitsValueSourceComment

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Annual bookstore sales in US, 2009USD mn16,907http://www.census.gov/retail/index.html#mrts16.9bn in 2008 according to census; assuming 2009 was as good

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% of sales that is books%50%Assumption

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Annual book salesUSD mn8,454=C2*C3

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Share of book titles where ebooks are available%30%Assumption

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Share of ebook sales where both paper and ebook formats are available%35%http://www.businessinsider.com/henry-blodget-kindle-sales-now-a-shocking-35-of-book-sales-when-kindle-version-available-2009-5Extrapolating Amazon numbers to the industry; http://xkcd.com/605/

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Annual ebook salesUSD mn888=C4*C5*C6

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Amazon's market share in ebooks%90%http://www.businessweek.com/news/2010-02-16/amazon-e-book-market-share-to-fall-as-industry-grows-update1-.html

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Amazon ebook salesUSD mn799=C7*C8

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Average ebook priceUSD9.99Assumption

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Amazon ebook salesmn80=C9/C10

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Number of Kindles soldmn3http://techcrunch.com/2010/01/29/3-million-amazon-kindles-sold-apparently/

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Average # of books per Kindlepcs27=C11/C12

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