During the plantation era, cinnamon, vanilla and copra were the chief exports. In 1965, during a three-month visit to the islands, futurist Donald Prell prepared for the then-crown colony's Governor General an economic report containing a scenario for the future of the economy.  Quoting from his report, in the 1960s, about 33% of the working population worked at plantations, and 20% worked in the public or government sector. The Indian Ocean Tracking Station on Mahé used by the Air Force Satellite Control Network was closed in August 1996 after the Seychelles government attempted to raise the rent to more than $10,000,000 per year.