The 2009 Kenya Population and Housing Census reported Kibera's population as 170,070. The Kibera slum was previously thought to be one of the biggest informal urban settlements in the world. Several actors had provided and published over the years growing estimations of the size of its population, most of them stating that it was the largest slum in Africa with the number of people there reaching over 1 million. According to Mike Davis, a well known expert on urban slums, Kibera had a population of about 800,000 people.