Question: What was the population of the city that is found in the same county as Eric Marcus Municipal Airport in 1900?

Knowledge 1: Eric Marcus Municipal Airport
Eric Marcus Municipal Airport is a county-owned, public-use airport in Pima County, Arizona, United States. It is located north of the central business district of Ajo and is about southwest of Phoenix. The airport was renamed on February 11, 2006; it was formerly known as Ajo Municipal Airport. [SEP] Knowledge 2: Tucson, Arizona
By 1900, 7,531 people lived in the city. The population increased gradually to 13,913 in 1910. At about this time, the U.S. Veterans Administration had begun construction on the present Veterans Hospital. Many veterans who had been gassed in World War I and were in need of respiratory therapy began coming to Tucson after the war, due to the clean dry air. Over the following years the city continued to grow, with the population increasing to 20,292 in 1920 and 36,818 in 1940. In 2006 the population of Pima County, in which Tucson is located, passed one million while the City of Tucson's population was 535,000. [SEP] Knowledge 3: Pima County Natural Resources, Parks and Recreation
Pima County Natural Resources, Parks and Recreation is the agency within Pima County, Arizona that manages the natural resources, parks, and recreation offerings within Pima County including Tucson, AZ.
Knowledge 1: Pima County Natural Resources, Parks and Recreation
Pima County Natural Resources, Parks and Recreation is the agency within Pima County, Arizona that manages the natural resources, parks, and recreation offerings within Pima County including Tucson, AZ. [SEP] Knowledge 2: Tucson, Arizona
By 1900, 7,531 people lived in the city. The population increased gradually to 13,913 in 1910. At about this time, the U.S. Veterans Administration had begun construction on the present Veterans Hospital. Many veterans who had been gassed in World War I and were in need of respiratory therapy began coming to Tucson after the war, due to the clean dry air. Over the following years the city continued to grow, with the population increasing to 20,292 in 1920 and 36,818 in 1940. In 2006 the population of Pima County, in which Tucson is located, passed one million while the City of Tucson's population was 535,000. [SEP] Knowledge 3: Eric Marcus Municipal Airport
Eric Marcus Municipal Airport is a county-owned, public-use airport in Pima County, Arizona, United States. It is located north of the central business district of Ajo and is about southwest of Phoenix. The airport was renamed on February 11, 2006; it was formerly known as Ajo Municipal Airport.
Knowledge 1: Eric Marcus Municipal Airport
Eric Marcus Municipal Airport is a county-owned, public-use airport in Pima County, Arizona, United States. It is located north of the central business district of Ajo and is about southwest of Phoenix. The airport was renamed on February 11, 2006; it was formerly known as Ajo Municipal Airport. [SEP] Knowledge 2: Tucson, Arizona
By 1900, 7,531 people lived in the city. The population increased gradually to 13,913 in 1910. At about this time, the U.S. Veterans Administration had begun construction on the present Veterans Hospital. Many veterans who had been gassed in World War I and were in need of respiratory therapy began coming to Tucson after the war, due to the clean dry air. Over the following years the city continued to grow, with the population increasing to 20,292 in 1920 and 36,818 in 1940. In 2006 the population of Pima County, in which Tucson is located, passed one million while the City of Tucson's population was 535,000. [SEP] Knowledge 3: Federalism
Usually, a federation is formed at two levels: the central government and the regions (states, provinces, territories), and little to nothing is said about second or third level administrative political entities. Brazil is an exception, because the 1988 Constitution included the municipalities as autonomous political entities making the federation tripartite, encompassing the Union, the States, and the municipalities. Each state is divided into municipalities (municípios) with their own legislative council (câmara de vereadores) and a mayor (prefeito), which are partly autonomous from both Federal and State Government. Each municipality has a "little constitution", called "organic law" (lei orgânica). Mexico is an intermediate case, in that municipalities are granted full-autonomy by the federal constitution and their existence as autonomous entities (municipio libre, "free municipality") is established by the federal government and cannot be revoked by the states' constitutions. Moreover, the federal constitution determines which powers and competencies belong exclusively to the municipalities and not to the constituent states. However, municipalities do not have an elected legislative assembly.

Answer: 7,531