The Nikkei stock index tumbled over 2,000 points to register its second-largest point drop in history, in a global market rout stirred by concerns over a U.S. recession following weaker-than-expected economic data. The 225-issue Nikkei Stock Average ended down 2,216.63 points, or 5.81 percent, from Thursday at 35,909.70, its lowest closing since Jan. 26. The broader Topix index finished 166.09 points, or 6.14 percent, lower at 2,537.60. A risk-off mood prevailed, with every industry category on the top-tier Prime Market losing ground, led by securities house, insurance and bank issues.