The iPhone’s market share in Japan has more than doubled in the past year to 72 percent, according to Tokyo-based research firm MM Research Institute. BusinessWeek reports that MM Research estimates shipments of the iPhone climbed to 1.69 million units in the year ending March 31, bringing the total sold since 2008 to 2.3 million. “Last year was just the beginning of the smartphone competition, which is why Apple did so well,” said Calvin…
