CAPE TOWN (Reuters) - Robust economic growth in Africa over the last decade has swelled the size of its middle class to a third of the continent's billion-strong population, according to a report released on Friday.

The African Development Bank (AfDB) study said 313 million Africans could now be classified as middle class, compared with 151 million in 1990 and 196 million in 2000.

The figures are further evidence of the growing consumer clout of the poorest continent, although the AfDB did qualify its findings by saying that 60 percent of the middle class "were barely out of the poor category".

"Sales of refrigerators, television sets, mobile phones, motors and automobiles have surged in virtually every country in recent years," the report said.

As an example, it cited an 81 percent increase since 2006 in the possession of cars and motorcycles in Ghana, whose economy may expand as much as 12 percent this year due to the start of commercial oil production in December.

South Africa, far and away the continent's biggest economy, ranked top in terms of vehicle ownership, with 300 vehicles per 1,000 people in 2007, more than twice as many as five years earlier.

Typically, middle class Africans would also own their own houses, opt for private rather than state medical care and spend more on food and schooling for their children, the report said.

The north African states of Tunisia, Morocco, Egypt and Algeria fared best in the overall assessment, with more than 75 percent of their populations ranked as middle class.

Gabon and Botswana, both small, resource-rich states, came top among sub-Saharan countries.

In Nigeria and Ethiopia, Africa's two most-populous nations with 230 million people between them, the middle classes made up 22 percent of the population, the report said.

As its yardstick, the AfDB defined 'middle class' as a person who spends between $2 and $20 a day at 2005 prices.

Source: Reuters