Hong Kong is one of the most densely populated areas in the world, with an overall density of some 6,300 people per square kilometre. At the same time, Hong Kong has one of the world's lowest birth rates—1.11 per woman of child-bearing age as of 2012, far below the replacement rate of 2.1. It is estimated that 26.8% of the population will be aged 65 or more in 2033, up from 12.1% in 2005. Hong Kong recorded 8.2 births per 1,000 people in 2005–2010.