Falls among stocks of big Japanese exporters took the Nikkei 225 Average down 233.54 to 10,208.05 at the close, and the more widely based Topix index dropped 14.82 points to 985.12, its lowest in more than three years. Stocks in companies which count on the US for their major revenues were among the worst hit, with consumer electronics giant Sony down almost 6%, while Canon, which gets 70% of its revenue from overseas, lost 2.6%. The most heavily traded stock was electronics giant Matsushita Electric, which shed almost 5%.