China's growth has slowed recently, but it remains a hotspot for billionaires. The country added 10 new billionaires over the last year.

That number might have been even higher, but some wealthy residents decided to take their money beyond the mainland recently -- giving Hong Kong and other Asian cities a boost. The moves were apparently sparked by concerns about China's ongoing credit crunch and a recent anti-corruption campaign that targeted luxury spending, according to Wealth-X.

To be ultra rich in China, think manufacturing. A full 17% of the country's wealthiest, those with $30 million or more in assets, derived their wealth from that sector.