According to a United Nation’s research, Lisbon and Tagus valley will house 45 per cent of the country’s total population by 2015, raising the current level of 3,800,000 inhabitants to 4,500,000. The report also says that 24 per cent of the total population will be living in the greater Porto region by that time, making this the second largest urban settlement; it also claims that, by 2015, only 22 per cent of the population will live in rural areas. It suggests that large Spanish cities along the common border may well become major urban centres for Portuguese residents.