Niamey's population has grown exponentially since independence - the droughts of the early 1970s and 1980s, along with the economic crisis of the early 1980s, have propelled an exodus of rural inhabitants to Niger's largest city. Its population increased gradually, from about 3,000 in 1930 to about 30,000 in 1960, rising to 250,000 in 1980 and, according to the official statistics, to 800,000 in 2000. Under the military government of General Seyni Kountché, there were strict controls on residency and the government would regularly round up and "deport" those without permits back to their villages. The growing freedoms of the late 1980s and 1990s, along with the Tuareg Rebellion of the 1990s and famine in the 2000s, have reinforced this process of internal migration, with large informal settlements appearing on the outskirts of the city. Noticeable in the city's centre since the 1980s are groups of poor, young, or handicapped beggars. Within the richer or more trafficked neighbourhoods, these beggars have in fact formed a well-regulated hierarchical system in which beggars garner ''sadaka'' according to cultural and religious norms.