Extending its fall for the eighth straight session, the Sensex at the Bombay Stock Exchange closed 65 points, or 0.4 percent lower, at 18,469, today, as investors continued to offload stocks, on worries about high interest rates impacting growth. The Sensex has already lost nearly 1,100 points in the last seven trading sessions. The Nifty at the National Stock Exchange declined 28 points, or 0.5 percent, to 5,537.Stock markets in China, Hong Kong, South Korea and Singapore lost between 1 percent and 2.3 percent.