There's nothing average about them, but if you had to use that word, the billionaire's club's average net worth is about $3 billion. They have between them $7.3 trillion, which is larger than the GDP of, say, Japan. 55% of billionaires are self-made--though tht's hard to measure exactly. Is someone who starts off with a few million and turns it into a billion "self-made"? It's an astonishing feat--most multimillionaires never accomplish it--but those are nice bootstraps to pull up on.
Still, many billionaires began with little. Jack Ma, Michael Bloomberg, Oprah Winfrey, Larry Ellison and What's App founder Jan Koum, for example, didn't have nest eggs when they flew. The US has the most billionaires, but they're really everywhere. 35% of billionaires don't have a college degree. The college, though, who has the most billionaire alumni is the University of Pennsylvania.
*data from the Wealth-X Billionaire Census 2014
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