The total number of billionaires reached 2,158 last year, up 9% from 2016, according to a new report from UBS and PwC. The growth was fastest in Asia, with China minting roughly one new billionaire every three days. Asian billionaires will be wealthier than their American peers in less than three years. The rich are getting richer and more numerous. The world added 332 billionaires last year, with their cumulative wealth increasing 19% to a record $8.9 trillion, according to an annual survey from UBS and PwC. What's behind this phenomenon? Explosive wealth creation in China.