In sub-Saharan Africa, some 49 per cent of the population lives on less than $1 a day and 70 per cent in urban slums, and their numbers are expected to double, on average, every 15 years.
在撒南非洲，大约49%的居民的日生活费不足1美元，70%的人生活在城市贫民区，而且预计平均每过15年这个数字就会翻一番。