The US dollar has kept as a position of key currency in the global economy in the changing international monetary system where the euro was introduced to some states of the EU in 1999. It is an evidence of inertia of the US dollar as a key currency. Our previous study (Ogawa and Muto, 2017b) conducted empirical analysis to investigate effects of several events on inertia of the US dollar. One of our findings was that the introduction of the euro increased utility of euro while utility of US dollar was kept unchanged. This paper examines the effects of the global financial crisis and the euro zone crisis as well as the introduction of the euro on the utility of the Japanese yen. The introduction of the euro significantly decreased the utility of the Japanese yen. It indicates that the introduction of the euro increased the utility of the euro while reducing the utility of the Japanese yen rather than the utility of the US dollar. The utility of the Japanese yen has significantly decreased while the global financial crisis and the euro zone crisis occurred. The Japanese yen has a declining trend in terms of its utility over time in the changing international monetary system.

中文翻译：

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不断变化的国际货币体系中日元贬值

在不断变化的国际货币体系（美元于1999年将欧元引入欧盟的某些国家）中，美元一直是全球经济中主要货币的地位。这证明了美元作为主要货币的惯性。我们之前的研究（Ogawa和Muto，2017b）进行了实证分析，以调查若干事件对美元惯性的影响。我们的发现之一是，欧元的引入增加了欧元的效用，而美元的效用却保持不变。本文研究了全球金融危机和欧元区危机的影响，以及欧元对日元效用的引入。欧元的引入大大降低了日元的效用。它表明，欧元的引入增加了欧元的效用，同时降低了日元的效用，而不是美元的效用。在发生全球金融危机和欧元区危机时，日元的效用已大大下降。在不断变化的国际货币体系中，日元的效用随时间呈下降趋势。