There is increasing evidence that export diversification is linked to growth. However, possibly less than 10 African countries show signs of export diversification, with manufacturing making up at least 25% of total exports. Botswana and Zambia are both heavily reliant on primary commodity exports. In Zambia, the dominance of copper was such that only 6% of Gross Domestic Product (GDP) was manufacturing at independence in 1964 – 90% of export revenues were with copper. Zambia has had two main eras of economic policy since independence, with a central planning approach in the first period. In 1991 Zambia evolved to a market economy model. Policies and the role of government differed – from that of investor to facilitator – but the outcome was similar: mineral exports have remained high and dominate the portfolio of goods exported.