Services is the largest sector of the Rwanda's economy and accounts for 53 percent of total GDP. Within services, the most important sub-sectors are: real estate activities (8 percent), wholesale and retail trade (8 percent), cultural, domestic & other services (6 percent), administrative and support service activities and public administration and defence; and compulsory social security (5 percent each). Agriculture, forestry and fishing account for 29 percent of GDP, with food crops contributing 17 percent. The industrial sector constitutes 18 percent of the GDP, with construction (7 percent) and manufacturing (6 percent) accounting for the largest shares. On the expenditure side, household consumption is the main component of GDP and accounts for 76 percent of its total use, followed by gross fixed capital formation (28 percent) and government expenditure (16 percent). Exports of goods and services account for 19 percent of GDP while imports account for 39 percent, subtracting 20 percent of total GDP. The major source of foreign trade is coffee, tea, tin cassiterite, wolframite and pyrethrum.