type of North–South divide that existed after World War II between First world, more developed, industrialized, wealthy countries and Third world countries, primarily as measured by GDP. From around 1980, however, through at least 2011, the GDP gap, while still wide, appeared to be closing and, in some more rapidly developing countries, life expectancies began to rise. However, there are numerous limitations of GDP as an economic indicator of social "well-being." If we look at the Gini coefficient for world income, over time, after World War II the global Gini coefficient sat at just under .45. From around 1959 to 1966, the global Gini increased sharply, to a peak of around .48 in 1966. After falling and leveling off a couple of times during a period from around 1967 to 1984, the Gini began to climb again in the mid-eighties until reaching a high or around .54 in 2000 then jumped again to around .70 in 2002. Since the late 1980s, the gap between some regions has markedly narrowed— between Asia and the advanced economies of the West, for example—but huge gaps remain globally. Overall equality across humanity, considered as individuals, has improved very little. Within the decade between 2003 and 2013, income inequality grew even in traditionally egalitarian countries like Germany, Sweden and Denmark. With a few exceptions—France, Japan, Spain—the top 10 percent of earners in most advanced economies raced ahead, while the bottom 10 percent fell further behind. By 2013, a tiny elite of multibillionaires, 85 to be exact, had amassed wealth equivalent to all the wealth owned by the poorest half (3.5 billion) of the world's total population of 7 billion. Country of citizenship (an ascribed status characteristic) explains 60% of variability in global income; citizenship and parental income class (both ascribed status characteristics) combined explain more than 80% of income variability. Inequality and economic growth The concept of economic growth is fundamental in capitalist economies. Productivity must grow as population grows and capital must grow to feed into increased productivity. Investment of capital leads to returns on investment (ROI) and increased capital accumulation. The hypothesis that economic inequality is a necessary precondition for economic growth has been a mainstay of liberal economic theory. Recent research, particularly over the first two decades of the 21st century, has called this basic assumption into question. While growing inequality does have a positive correlation with economic growth under specific sets