Zersiedelung
The registered population of Beijing Municipality consists of people holding either Beijing permanent residence "hukou permits" or temporary residence permits. The 2010 census revealed that the official total population in Beijing was 19,612,368, representing a 44% increase over the last decade. In 2006, the population of the urban core was 13.33 million, 84.3 percent of the total municipal population, which officially stood at 15.81 million. Urban sprawl continues at a rapid pace.