average 30–40% returns for telecommunications (ICT) investments, over 40% for electricity generation and 80% for roads. In Africa, it is argued that in order to meet the MDGs by 2015 infrastructure investments would need to reach about 15% of GDP (around $93 billion a year). Currently, the source of financing varies significantly across sectors. Some sectors are dominated by state spending, others by overseas development aid (ODA) and yet others by private investors. In sub-Saharan Africa, the state spends around $9.4 billion out of a total of $24.9 billion. In irrigation, SSA states represent almost all spending; in transport and energy a majority of investment is state spending; in ICT and water supply and sanitation, the private sector represents the majority of capital expenditure. Overall, aid, the private sector and non-OECD financiers between them exceed state spending. The private sector spending alone equals state capital expenditure, though the majority is focused on ICT infrastructure investments. External financing increased from $7 billion (2002) to $27 billion (2009). China, in particular, has emerged as an important investor. Oil and minerals The region is a major exporter to the world of gold, uranium, chromium, vanadium, antimony, coltan, bauxite, iron ore, copper, and manganese. South Africa is a major exporter of manganese as well as chromium. A 2001 estimate is that 42% of the world's reserves of chromium may be found in South Africa. South Africa is the largest producer of platinum, with 80% of the total world's annual mine production and 88% of the world's platinum reserve. Sub-Saharan Africa produces 33% of the world's bauxite, with Guinea as the major supplier. Zambia is a major producer of copper. The Democratic Republic of Congo is a major source of coltan. Production from DR Congo is very small, but the country has 80% of the proven reserves in Africa, which are 80% of those worldwide. Sub-Saharan Africa is a major producer of gold, producing up to 30% of global production. Major suppliers are South Africa, Ghana, Zimbabwe, Tanzania, Guinea, and Mali. South Africa had been first in the world in terms of gold production since 1905, but in 2007 it moved to second place, according to GFMS, the precious metals consultancy. Uranium is major commodity from the region. Significant suppliers are Niger, Namibia, and South Africa. Namibia was the number one supplier from sub-Saharan Africa in 2008. The region produces 49% of the world's diamonds.