Japan's Nikkei Stock Average ended Friday above the 20,000 threshold for the first time since December 2015, as robust U.S. economic data and a weaker yen boosted market sentiment.The 225-issue Nikkei Stock Average ended up 317.25 points, or 1.60 percent, from Thursday at 20,177.28, its highest close since August 2015. The broader Topix index of all First Section issues on the Tokyo Stock Exchange finished 26.06 points, or 1.64 percent, higher at 1,612.20.Gainers were led by iron and steel, securities and marine transportation issues.The Nikkei topped the 20,000 line from the outset after b…READ FULL ARTICLE