The website Howmuch published an interesting map about billionaires by country and the source of their wealth.
United States as it is the largest economy in the world, also it is the first place in numbers of billionaires, 30% of the total. Most of the billionaires of the U.S source of wealth was due to entrepreneurship, 32.1% and only 3.8% was due political connections, 28.9% inherited and 26.8% made fortune in the financial sector. Meanwhile in Russia 64% became billionaire due political connections.
A common source of wealth in european countries is inheritance, all finish billionaires inherited their fortune, Finland is followed by Denmark with 83.3%, Germany 64.7% and Sweden with 63.2%. In the rest of the world Kuwait, South Korea and Egipt have comparable inheritance numbers.
China, the second highest GDP is also the second in numbers of billionaires (9.2%), 40.1% got their fortune founding companies, 25% being executives and 23.7% due to the financial sector. In Japan, most of the billionaires are company founders (63%).
In the americas the second places goes to Brazil, in which 47.7% inherited, 21.5% are company founders and 18.5% due to the financial sector.