What is now Ecuador formed part of the northern Inca Empire until the Spanish conquest in 1533. A border war with Peru that flared in 1995 was resolved in 1999. Ecuador has substantial petroleum resources and rich agricultural areas. Because the country exports primary products such as oil, bananas, flowers and shrimp, fluctuations in world market prices can have a substantial domestic impact. In the late 1990s, Ecuador suffered its worst economic crisis, with natural disasters and sharp declines in world petroleum prices driving Ecuador's economy into free fall in 1999. Real GDP contracted by more than 6%, with poverty worsening significantly.In March 2000, Congress approved a series of structural reforms that also provided the framework for the adoption of the US dollar as legal tender. Dollarization stabilized the economy, and growth returned to its pre-crisis levels in the years that followed. Under the administration of Lucio Gutierrez from January 2003 to April 2005 ,Ecuador benefited from higher world petroleum prices. However, the government under Alfredo Palacio reversed economic reforms that reduced Ecuador's vulnerability to petroleum price swings and financial crises, allowing the central government greater access to oil windfalls and disbursing surplus retirement funds.