Horizonte metropolitan area. Whilst the majority of the largest metropolitan areas are within Brazil, Argentina is host to the second largest metropolitan area by population in South America: the Buenos Aires metropolitan region is above 13 million inhabitants. South America has also been witness to the growth of megapolitan areas. In Brazil four megaregions exist including the Expanded Metropolitan Complex of São Paulo with more than 32 million inhabitants. The others are the Greater Rio, Greater Belo Horizonte and Greater Porto Alegre. Colombia also has four megaregions which comprise 72% of its population, followed by Venezuela, Argentina and Peru which are also homes of megaregions. The top ten largest South American metropolitan areas by population as of 2015, based on national census numbers from each country: 2015 Census figures. Economy South America relies less on the export of both manufactured goods and natural resources than the world average; merchandise exports from the continent were 16% of GDP on an exchange rate basis, compared to 25% for the world as a whole. Brazil (the seventh largest economy in the world and the largest in South America) leads in terms of merchandise exports at $251 billion, followed by Venezuela at $93 billion, Chile at $86 billion, and Argentina at $84 billion. Since 1930, the continent has experienced remarkable growth and diversification in most economic sectors. Most agricultural and livestock products are destined for the domestic market and local consumption. However, the export of agricultural products is essential for the balance of trade in most countries. The main agrarian crops are export crops, such as soy and wheat. The production of staple foods such as vegetables, corn or beans is large, but focused on domestic consumption. Livestock raising for meat exports is important in Argentina, Paraguay, Uruguay and Colombia. In tropical regions the most important crops are coffee, cocoa and bananas, mainly in Brazil, Colombia and Ecuador. Traditionally, the countries producing sugar for export are Peru, Guyana and Suriname, and in Brazil, sugar cane is also used to make ethanol. On the coast of Peru, northeast and south of Brazil, cotton is grown. 50.5% of the South America's land surface is covered by forest, but timber industries are small and directed to domestic markets. In recent years, however, transnational companies have been settling in the Amazon to exploit noble timber destined for export. The Pacific coastal waters of South America are the most