The Nikkei stock index gained about 3.6% Tuesday in Tokyo, ending above the 14,000 mark, its highest level in nearly five years, as sentiment was buoyed following robust US jobs data for April and the yen’s weak tone against the US dollar. The 225-issue Nikkei Stock Average finished up 486.20 points, or 3.55%, from Thursday at 14,180.24, the highest closing level since June 18, 2008, when it closed at 14,452.82. The broader Topix index of all First Section issues on the Tokyo Stock Exchange rose 35.29 points, or 3.06%, to 1,188.57, Japan’s news agency (Kyodo) reported. Japanese financial markets were closed Friday and Monday for national holidays.