Uncertainty may be the watchword for the global economy today but the past 40 years have been a period of increasing wealth and living standards around the world. Data from the World Bank shows that the number of low-income countries has halved since 1987, while the number of countries classified as high-income has more than doubled. More than half of the respondents surveyed for the World Economic Forum's latest Chief Economists' Outlook expect greater divergence between the growth of developin