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.
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Question: During the years 1940-1955, the rate of decline in the U.S. death rate accelerated from 2% per year to 8% per year, then returned to the historical rate of 2% per year. The dramatic decline in the immediate post-war years has been attributed to the rapid development of new treatments and vaccines for infectious disease that occurred during these years. Vaccine development continued to accelerate, with the most notable achievement of the period being Jonas Salk's 1954 development of the polio vaccine under the funding of the non-profit National Foundation for Infantile Paralysis. The vaccine process was never patented, but was instead given to pharmaceutical companies to manufacture as a low-cost generic. In 1960 Maurice Hilleman of Merck Sharp & Dohme identified the SV40 virus, which was later shown to cause tumors in many mammalian species. It was later determined that SV40 was present as a contaminant in polio vaccine lots that had been administered to 90% of the children in the United States. The contamination appears to have originated both in the original cell stock and in monkey tissue used for production. In 2004 the United States Cancer Institute announced that it had concluded that SV40 is not associated with cancer in people.

Answer: When was the Polio vaccine created?


Question: According to China daily. Fifteen years after the satellite system was launched, it is now generating $31.5 billion for major companies such as China Aerospace Science and Industry Corp, AutoNavi Holdings Ltd, and China North Industries Group Corp.

Answer: How long ago was the BeiDou Satellite System first launched?


Question: During the early 2000s, the USAF fumbled several high profile aircraft procurement projects, such as the missteps on the KC-X program. Winslow Wheeler has written that this pattern represents "failures of intellect and – much more importantly – ethics." As a result, the USAF fleet is setting new records for average aircraft age and needs to replace its fleets of fighters, bombers, airborne tankers, and airborne warning aircraft, in an age of restrictive defense budgets. Finally in the midst of scandal and failure in maintaining its nuclear arsenal, the civilian and military leaders of the air force were replaced in 2008.

Answer:
When did the USAF have several missteps of aircraft procurement projects?