Map of Visaginas for In May 1985, the Nikkei Dow Jones Stock Price Average became the Nikkei Stock Average and at the same time the Nikkei Dow Jones 500 Stock Average became the Nikkei 500 Stock Average. Since 1971, the Nikkei has been calculated by Nihon Keizai Shimbun, Inc. (NKS) the leading Japanese financial information services company, therefore any addition or removal of stocks is at the discretion of NKS. Because of the method of calculation, the composition of the selected stock, and the historical continuity of the Nikkei, most market reports quote the Nikkei when they talk about the Japanese stock market. The Nikkei has continued to develop and expand. On January 4, 1982, the Nikkei Dow-Jones 500 Stock Average was introduced, covering an adjusted average for 500 stocks. Since October 1, 1985, the index has been calculated every minute during trading hours. Map of Visaginas 2016.