Even though the population of South Africa has grown in the past decade (mostly because of immigration), the country had an yearly population growth rate of −0.501% in 2008 (CIA est.), counting immigration. The CIA thinks that in 2009 South Africa's population started to grow again, at a rate of 0.281%. South Africa is home to an estimated 5 million illegal immigrants, counting about 3 million Zimbabweans. A series of anti-immigrant riots happened in South Africa beginning on 11 May 2008.