The economy of Cameroon is to a certain extent dependent on agriculture, which is the main occupation of about 70 percent of Cameroon's population. Then the country has a rich resource of timber but the main source of revenue is generated through petroleum reserves. The country has also large reserves of bauxite and natural gas, though they have yet to be exploited. Hydroelectric power stations on Cameroon's rivers, particularly the Sanaga, provide enough electricity to meet almost all of the country's needs. In 1999, the national budget showed revenues of $1.4 billion and expenditures of $1.4 billion.