South Africa's black middle class is driving a post-apartheid consumer boom in the country, a report has said. The group is responsible for almost a quarter of the 600bn rand ($96m) spent yearly by consumers, the University of Cape Town's Black Diamond study said. Government measures to bring the sector into the mainstream economy have helped its growth, the report added. The black middle class, making up two million of the 45 million population, is expected to grow by 50% a year.