; it was hampered in the late 1980s by weak prices on world markets. Bolivia has long been one of the world's leading producers of tin. Petroleum and natural gas production increased in importance in the 1960s and early 1970s; by the early 1990s Bolivia was self-sufficient in petroleum and was exporting significant amounts of natural gas to Argentina. Although Bolivia has long been dependent on mineral exports, declining tin prices and increased petroleum and natural gas production changed the nature of the country's economy in the 1980s. By the early 1990s, natural gas accounted for 27 percent of export earnings while tin provided just 12 percent. Bolivia's imports consist mainly of machinery, motor vehicles, electric equipment, and manufactured goods. Agriculture is extremely important to the Bolivian economy, employing two percent of the labor force. Bolivia's agriculture suffers from antiquated farming methods, uneven population distribution, and inadequate transportation. Although now self-sufficient in the production of sugar, rice, and meat, Bolivia must still import certain foodstuffs. The main Bolivian crops are soybeans, sugar, chestnuts, potatoes, cassava, bananas, maize, rice, plantains, and citrus fruits. Fishing is a relatively unimportant industry in landlocked Bolivia. The basic unit of currency is the boliviano, equivalent to 1 million old Bolivian pesos. Banking is very limited because the majority of the country is impoverished. Bolivia's labor force was 3.2 million in 1998. Nearly the entire non-farming labor force is organized, most of it in unions belonging to the Central Obrera Boliviana, the central labor federation.Structurally and climatically, Bolivia consists of two main regions: the highlands and the eastern lowlands, divided between the Amazon and Parana basins. The highlands of Bolivia consist of three distinct parts: the Cordillera Occidental; the Altiplano, and the Cordillera Oriental. The Cordi...
