sentences:  By 1825 the figure may have been as high as 56%.In 1826, the first article of an agreement drafted in Rio de Janeiro stated that it should not be “lawful for the subjects of the Emperor of Brazil to be concerned in the carrying on of the African slave trade, under any pretext or in any manner whatever, and the carrying on of such after that period, by any person, subject of His Imperial Majesty, shall [should] be deemed and treated as piracy.” The announcement of this treaty caused great excitement in Brazil, for many believed it meant immediate suspension of the slave trade.However, when coffee production exploded in the 1830s in Rio de Janeiro as the crop that would fuel the export economy for the next 140 years, this new demand on the trade was not quelled by the treaty.