Malawi has an agro-based economy with the agriculture sector accounting for over 35.5 per cent of GDP, employing about 84.5 percent of labour force and accounting for 82.5 percent of foreign exchange earnings. Agriculture is characterized by a dual structure consisting of commercial estates that grow cash crops and a large smallholder sub-sector that is mainly engaged in mixed subsistence farming. Maize, the staple food, accounts for 80 percent of cultivated land in the small-holder sub-sector. The main agricultural export crop is tobacco, followed by tea, sugar and coffee. The manufacturing sector accounts for 11 percent of GDP and comprises mainly agro-processing activities in the tobacco, tea and sugar industries. Distribution and services represent about 22 percent of GDP. While Malawi is not endowed with mineral resources on the scale of its neighbouring countries, there is significant potential for natural resource extraction. Minerals that can be found include uranium, gold, coal, bauxite, phosphates, graphite, granite, black granite, vermilite, aquamarine, tourmaline, rubies, sapphire and rare earths.