The benchmark Nikkei index plunged 5 percent to a 20-month low Tuesday, tracking drops on Wall Street since late last week amid concerns over a slowdown in the world's largest economy, with exporter stocks also hurt by a strong yen.The 225-issue Nikkei Stock Average ended down 1,010.45 points, or 5.01 percent, from Friday at 19,155.74, the lowest level since April 2017. Financial markets were closed Monday in Tokyo for a national holiday. The broader Topix index of all First Section issues on the Tokyo Stock Exchange finished 72.64 points, or 4.88 percent, lower at 1,415.55.All sectors fell…READ FULL ARTICLE