Amazon famously refuses to disclose the size and profitability of its cloud offerings, hiding Amazon Web Services revenue in a category with co-branded credit cards in its quarterly reports.

However, with the help of analysts and cloud optimization companies such as Newvem, we have a few good guesses.

While Azure is about a billion-dollar business for Microsoft, Amazon likely will almost quadruple that revenue in 2013, with about a third of the $6.2 billion public cloud market in 2012 and an estimated $3.8 billion revenue this year. Even better for Amazon shareholders, some analysts say that AWS is a 100 percent profit business unit.

That dollars-and-cents growth is dependent, of course, on actual cloud services customers, which are predicted to host 11.6 million websites on Amazon in 2013, up sharply from 6.8 million in 2012. Most of those are in the U.S. — just over half — but 34 percent are in Europe and Russia. Nine percent are in South America, with 5 percent in Australia and just 1 percent in Africa.

Here’s all the data, in visual form.

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