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.  

Example Input: Sentence: In September 1695, Captain Henry Every, an English pirate on board the Fancy, reached the Straits of Bab-el-Mandeb, where he teamed up with five other pirate captains to make an attack on the Indian fleet making the annual voyage to Mocha. The Mughal convoy included the treasure-laden Ganj-i-Sawai, reported to be the greatest in the Mughal fleet and the largest ship operational in the Indian Ocean, and its escort, the Fateh Muhammed. They were spotted passing the straits en route to Surat. The pirates gave chase and caught up with Fateh Muhammed some days later, and meeting little resistance, took some £50,000 to £60,000 worth of treasure. 
Question: how often did the Indian fleet voyage to Mocha?
Example Output: annual

Example Input: Sentence: For 1890, the Census Office changed the design of the population questionnaire. Residents were still listed individually, but a new questionnaire sheet was used for each family. Additionally, this was the first year that the census distinguished between different East Asian races, such as Japanese and Chinese, due to increased immigration. This census also marked the beginning of the term "race" in the questionnaires. Enumerators were instructed to write "White," "Black," "Mulatto," "Quadroon," "Octoroon," "Chinese," "Japanese," or "Indian." 
Question: How often was a new questionnaire sheet used in the 1890 census?
Example Output: for each family

Example Input: Sentence: In the United States, the Environmental Protection Agency (EPA) is responsible for regulating pesticides under the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) and the Food Quality Protection Act (FQPA). Studies must be conducted to establish the conditions in which the material is safe to use and the effectiveness against the intended pest(s). The EPA regulates pesticides to ensure that these products do not pose adverse effects to humans or the environment. Pesticides produced before November 1984 continue to be reassessed in order to meet the current scientific and regulatory standards. All registered pesticides are reviewed every 15 years to ensure they meet the proper standards. During the registration process, a label is created. The label contains directions for proper use of the material in addition to safety restrictions. Based on acute toxicity, pesticides are assigned to a Toxicity Class. 
Question: How often are pesticides produced more recently evaluated for safety?
Example Output:
every 15 years