A new study by the London- based Center for Policy Studies found that next to Hong Kong, Israel has more self-made billionaires than any other country and Greece manged to be included in the top 20 list.

The report looked at 1,000 self-made billionaires, termed “SuperEntrepreneurs,” from 15 years’ worth of Forbes annual lists and calculated how many each country around the world produced in proportion to their total population. Those who inherited their fortunes were excluded.

Hong Kong led the list with 2.831 SuperEntrepreneurs per million inhabitants, followed by Israel with 1.788, the United States with 1.388, Switzerland with 1.229 and Singapore with 1.053. Greece and Portugal are in the 20th position.

Countries such as Greece, Turkey, Spain, Portugal and Italy had many self-employed people, but few self-made billionaires. The reason, according to the study, is that self-employed people also have to be innovative, developing new products and approaches to business. Greece and the other countries have few SuperEntrepreneurs per capita, compared with the US, Canada, Japan and Switzerland. Greece, for example, is characterised by a high proportion of self-employment, not because the Greek economy favours entrepreneurship but precisely because it doesn’t.

SuperEntrepreneurs tend to be well-educated, the study found. In the US, for example, SuperEntrepreneurs were five times more likely to hold a PhD as a member of the general population.

Critics of the study could note that with such a small number of SuperEntrepreneurs, the numbers could swing wildly with the addition or subtraction of just one individual. While the US boasted 411 self-made billionaires, Israel had just 13, and New Zealand, ranked 12th, had just two. To counter this problem, the study also looked at trends by region.

Overall, the report recommended that governments lower taxes, especially capital-gains taxes, and reduce burdensome regulation to unleash innovative entrepreneurs.