GLOBAL MARKETS-World share markets rise to 6-year high, euro gains

* S&P index set for biggest annual rise in 6 years * Japanese stocks on track for best year since 1972 * Euro near 5-year high vs yen, two-year high vs dollar * U.S. benchmark yields slip below 3 percent By Richard Leong NEW YORK, Dec 30 (Reuters) - World stock markets rose to a six-year high on Monday on optimism about the global economy heading into 2014, while the euro strengthened against the dollar and yen on comments by European Central Bank chief Mario Draghi. U.