Problem: The total population in sub-Saharan Africa is projected to increase to almost one billion people, making it the most populated region outside of South-Central Asia. According to the United Nations, the population of Nigeria will reach 411 million by 2050. Nigeria might then be the 3rd most populous country in the world. In 2100, the population of Nigeria may reach 794 million. While the overall population is expected to increase, the growth rate is estimated to decrease from 1.2 percent per year in 2010 to 0.4 percent per year in 2050. The birth rate is also projected to decrease from 20.7 to 13.7, while the death rate is projected to increase from 8.5 in 2010 to 9.8 in 2050. List of countries by life expectancy is all expected to increase from 67.0 years in 2010 to 75.2 years in 2050. By 2050 the percent of the population estimated to be living in urban areas is 69.6% compared to the 50.6% in 2010.
Answer this question based on the article: By how many percent is the growth rate estimated to decrease between 2010 and 2050?
A: .8

Problem: There were 810,388 households out of which 28.61% had children under the age of 18 living with them, 42.80% were Marriage living together, 15.28% had a female householder with no husband present, and 36.67% were non-families. 28.79% of all households were made up of individuals and 11.07% (3.31% male and 7.76% female) had someone living alone who was 65 years of age or older. The average household size was 2.52 and the average family size was 3.14.
Answer this question based on the article: Which group for households is smaller: Marriage living together or non-families?
A: non-families

Problem: Col. Edwin Sumner conducted a campaign against the Navajo in 1851. He delegated Maj. Electus Backus to build Fort Defiance in the middle of Dine bikeyah . Col Sumner entered Canyon de Chelly but Navajo harassment attacks caused him to withdraw. In 1855 a treaty was signed at Laguna Negra by Manuelito and Zarcillos Largos for the Navajo and Henry L. Dodge , Governor Merriweather, and General John Garland. Two years later a severe drought hit the Navajo and decimated their livestock and agricultural resources, causing a famine in the winter of 1857-1858. A time of social disruption ensued. Surrounding tribes gradually increased their attacks on the weakened Navajo. The Navajo demanded in 1858 that Fort Defiance stop grazing their livestock on prime Navajo land. Soldiers shot 48 cattle and 8 horses belonging to Manuelito. Navajo warriors killed a servant of the commanding officer in retaliation for the killing of their people's livestock without compensation. The United States military demanded the murderer be brought to them, or they would begin a war. The Miles Campaign was sent against them, leaving Fort Defiance on September 9.
Answer this question based on the article: How many years after Col Sumner began the campaign against the Navajo was the treaty was signed at Laguna Negra?
A:
4