This task is about reading the given passage and construct a question about the information present in the passage. Construct a question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) its answer is a continuous text span from the paragraph. Avoid creating questions that (i) can be answered correctly without actually understanding the paragraph and (ii) uses same words or phrases given in the passage.

Providing 25% of Namibia's revenue, mining is the single most important contributor to the economy. Namibia is the fourth largest exporter of non-fuel minerals in Africa and the world's fourth largest producer of uranium. There has been significant investment in uranium mining and Namibia is set to become the largest exporter of uranium by 2015. Rich alluvial diamond deposits make Namibia a primary source for gem-quality diamonds. While Namibia is known predominantly for its gem diamond and uranium deposits, a number of other minerals are extracted industrially such as lead, tungsten, gold, tin, fluorspar, manganese, marble, copper and zinc. There are offshore gas deposits in the Atlantic Ocean that are planned to be extracted in the future. According to "The Diamond Investigation", a book about the global diamond market, from 1978, De Beers, the largest diamond company, bought most of the Namibian diamonds, and would continue to do so, because "whatever government eventually comes to power they will need this revenue to survive".
How much revenue does mining provide Namibia?

Recently, the Air Force refined its understanding of the core duties and responsibilities it performs as a Military Service Branch, streamlining what previously were six distinctive capabilities and seventeen operational functions into twelve core functions to be used across the doctrine, organization, training, equipment, leadership, and education, personnel, and facilities spectrum. These core functions express the ways in which the Air Force is particularly and appropriately suited to contribute to national security, but they do not necessarily express every aspect of what the Air Force contributes to the nation. It should be emphasized that the core functions, by themselves, are not doctrinal constructs.
How many core functions did the Air Force reduce its duties down to recently? 

The majority of Paris' salaried employees fill 370,000 businesses services jobs, concentrated in the north-western 8th, 16th and 17th arrondissements. Paris' financial service companies are concentrated in the central-western 8th and 9th arrondissement banking and insurance district. Paris' department store district in the 1st, 6th, 8th and 9th arrondissements employ 10 percent of mostly female Paris workers, with 100,000 of these registered in the retail trade. Fourteen percent of Parisians work in hotels and restaurants and other services to individuals. Nineteen percent of Paris employees work for the State in either in administration or education. The majority of Paris' healthcare and social workers work at the hospitals and social housing concentrated in the peripheral 13th, 14th, 18th, 19th and 20th arrondissements. Outside Paris, the western Hauts-de-Seine department La Défense district specialising in finance, insurance and scientific research district, employs 144,600, and the north-eastern Seine-Saint-Denis audiovisual sector has 200 media firms and 10 major film studios.

In what districts are the majority of businesses service jobs located?