This task is about creating an unanswerable question based on a given passage. Construct a question that looks relevant to the given context but is unanswerable. Following are a few suggestions about how to create unanswerable questions:
(i) create questions which require satisfying a constraint that is not mentioned in the passage
(ii) create questions which require information beyond what is provided in the passage in order to answer
(iii) replace an existing entity, number, date mentioned in the passage with other entity, number, date and use it in the question
(iv) create a question which is answerable from the passage and then replace one or two words by their antonyms or insert/remove negation words to make it unanswerable.

Passage: The value of the U.S. dollar declined significantly during wartime, especially during the American Civil War, World War I, and World War II. The Federal Reserve, which was established in 1913, was designed to furnish an "elastic" currency subject to "substantial changes of quantity over short periods", which differed significantly from previous forms of high-powered money such as gold, national bank notes, and silver coins. Over the very long run, the prior gold standard kept prices stable—for instance, the price level and the value of the U.S. dollar in 1914 was not very different from the price level in the 1880s. The Federal Reserve initially succeeded in maintaining the value of the U.S. dollar and price stability, reversing the inflation caused by the First World War and stabilizing the value of the dollar during the 1920s, before presiding over a 30% deflation in U.S. prices in the 1930s.
During which times does the value of the dollar typically maintain value?