Since in Belém the proprietor of the commercial establishment and the employees were not able to understand João Gabriel's handwriting, or because he had hastily written "Acri" or "Aqri", instead of "Aquiri", the goods and the invoice arrived to the colonizer as having been sent to the Acre River. Acre possesses some nicknames: the End of Brazil, The Rubber Tree State, the Latex State and the Western End. The native inhabitants of Acre are called "acrianos, in the singular "acriano. Until the entry in force of the Orthographic Agreement of 1990, the correct spelling was "acreano in the singular and in the plural "acreanos. In 2009, with the new orthographic agreement, the change generated controversy between the Academy of Letters of Acre (Academia Acreana de Letras) and the Brazilian Academy of Letters (Academia Brasileira de Letras), alleging that the change would mean the denial of the state's historical and cultural roots, changing the last letter of the toponym from "E" to "I". The state of Acre occupies an area of 152,581 km2 (58,911 mi2) in the extreme west of Brazil. It is located at 70º west longitude and at 9º south latitude. In Brazil, the state is part of the North Region, forming borders with the states of Amazonas and Rondônia, and with two countries: Peru and Bolivia. Practically all of the terrain of the state of Acre is part of the low sandstone plateau, or terra firme, morphological unit which dominates most of the Brazilian Amazon. These terranes rise, in Acre, from the southeast to the northeast, with very tabular topography in general. In the extreme west is found the Serra da Contamana or Serra do Divisor, along the western border, with the highest altitudes in the state (). About 63% of the state's surface lies between in height; 16% between 300 and 609 (984 and 1,998 ft); and 21% between 200 and 135 (656 and 443 ft). The climate is hot and very humid, of the "Am" type in the Köppen climate classification system, and the monthly average temperatures vary between , being the lowest average of the North Region. The rainfall reaches an annual total of , with a clear dry season in the months of June, July, and August.