Tokyo--March 2--Japan's benchmark Nikkei index plunged 3.3% to a new 15-year closing low, dropping for the fifth straight day as stocks faced selling across the board. Market sentiment deteriorated due to disappointing economic indicators such as a record decline in the Tokyo core consumer price index and on news that Oracle Corp. (ORCL) earnings would fall short. The Nikkei ended down 419.86 points at 12,261.80, the lowest close since July 31, 1985.