There are four such global hot spots: the borders between the US and Mexico, Spain and Morocco, Greece (and Italy) and the southern Balkans, and Indonesia and Singapore (or Malaysia). The income gaps range from more than seven to one in the latter case to 4.5 to one in the case of Spain and Morocco, 4.3 to one between the US and Mexico, and four to one between Greece and Albania.
这就是为什么当今大多数充满争议的边界分隔了两边人们之间收入差异最大的经济体。一共有四个全球性的热点：美国和墨西哥、西班牙和摩洛哥、希腊（和意大利）和南巴尔干以及印尼和新加坡（或者马来西亚）之间的边界。收入差距从后者的超过七比一，西班牙和摩洛哥之间的4.5比1，美国和墨西哥之间的4.3比1一直到希腊和阿尔巴尼亚之间的四比一。