ByJohn S. McClenahen In Brazil, South America's largest economy, one of every eight adults is starting a business. But entrepreneurs are scarcer in Japan and Ireland, Europe's fastest growing economy, where only one in 100 adults is currently putting together a business, reveals a study from Babson College, the London Business School, and the Kauffman Center for Entrepreneurial Leadership at the Ewing Marion Kauffman Foundation, Kansas City. The rate in the U.S. is one in 10. Among the 21 nations surveyed, men start and operate most of the firms, with the majority of entrepreneurs ranging from 25-years-old to 34-years-old. The ratio of male-to-female entrepreneurs varies from 12 to 1 in France to less than 2 to 1 in Brazil and Spain. The average amount of venture capital invested in a company ranges from US$13.2 million in the U.S. to $485,000 in South Korea. And the survey results show that informal private investments in emerging and new businesses exceed formal venture capital outlays by nearly a 3-to-2 margin.