In this task, you're given passages that contain mentions of a time duration related quesry and we are supposed to write answer to a question that involves event “frequency", which refers to how often an event is likely to be repeated. For example, "taking showers" typically occurs ~5 times a week, "going to saturday market" usually happens every few weeks/months, etc. 
 Note that a lot of the questions could have more than one correct answers. We only need a single most-likely answer. Please try to keep your "answer" as simple as possible. Concise and simple "answer" is preferred over those complex and verbose ones.  

[EX Q]: Sentence: During the Cold War between the Soviet Union and the United States, huge stockpiles of uranium were amassed and tens of thousands of nuclear weapons were created using enriched uranium and plutonium made from uranium. Since the break-up of the Soviet Union in 1991, an estimated 600 short tons (540 metric tons) of highly enriched weapons grade uranium (enough to make 40,000 nuclear warheads) have been stored in often inadequately guarded facilities in the Russian Federation and several other former Soviet states. Police in Asia, Europe, and South America on at least 16 occasions from 1993 to 2005 have intercepted shipments of smuggled bomb-grade uranium or plutonium, most of which was from ex-Soviet sources. From 1993 to 2005 the Material Protection, Control, and Accounting Program, operated by the federal government of the United States, spent approximately US $550 million to help safeguard uranium and plutonium stockpiles in Russia. This money was used for improvements and security enhancements at research and storage facilities. Scientific American reported in February 2006 that in some of the facilities security consisted of chain link fences which were in severe states of disrepair. According to an interview from the article, one facility had been storing samples of enriched (weapons grade) uranium in a broom closet before the improvement project; another had been keeping track of its stock of nuclear warheads using index cards kept in a shoe box. 
Question: Approximately how many times did police capture shipments of bomb-grade plutonium or uranium between 1993 and 2005?
[EX A]: 16

[EX Q]: Sentence: Mechanical pulping yields almost a tonne of pulp per tonne of dry wood used, which is why mechanical pulps are sometimes referred to as "high yield" pulps. With almost twice the yield as chemical pulping, mechanical pulps is often cheaper. Mass-market paperback books and newspapers tend to use mechanical papers. Book publishers tend to use acid-free paper, made from fully bleached chemical pulps for hardback and trade paperback books. 
Question: How many times more yield does the mechanical pulping process produce when compared to to the chemical pulping process?
[EX A]: twice

[EX Q]: Sentence: The government of the Marshall Islands operates under a mixed parliamentary-presidential system as set forth in its Constitution. Elections are held every four years in universal suffrage (for all citizens above 18), with each of the twenty-four constituencies (see below) electing one or more representatives (senators) to the lower house of RMI's unicameral legislature, the Nitijela. (Majuro, the capital atoll, elects five senators.) The President, who is head of state as well as head of government, is elected by the 33 senators of the Nitijela. Four of the five Marshallese presidents who have been elected since the Constitution was adopted in 1979 have been traditional paramount chiefs. 
Question: How often are elections held in the Marshall Islands?
[EX A]:
every four years

