A U.S. Geological Survey valued Zambia’s copper and cobalt exports at approximately US$4bn in 2006. It is estimated that Zambia’s exports of these resources account for more than 85% of the country’s total exports. The Zambian state has adopted a mineral policy designed to augment investments in the mining sector and state-owned mining companies have been actively privatized since the year 2000. Investments in Zambia’s mining industry for 2007 were estimated at US$1bn. Nevertheless, the decline in the price of copper (from US$8,800 a tonne in 2006 to below US$4,000 a tonne by October 2008, since recovered to US $6,000) has significantly impacted investment in the country. In response to pressure from mining companies struggling with a global economic slowdown and the fall in metal prices, the Zambian government abolished a controversial 25% windfall tax on mining introduced a year earlier.