Japan's Nikkei 225 Stock Index Sinks 10% in Worst Losses Since 1987
Japan's Nikkei 225 index plunges 10%.
Heavy selling driven by U.S. economic concerns.
Nikkei down over 3,500 points, at 32,385.01.
Worst two-day decline since 1987.
Previous record decline was 14.9% on "Black Monday".
Tokyo stocks fall after Bank of Japan's rate hike.
Benchmark rate now at last year's level.