China, including Hong Kong, displaced the United States as Japan's biggest trade partner in 2004, Japanese Finance Ministry data showed. Trade volume totaled US$213.3bn, ahead of Japan-US trade volume of US$198.8bn. China-HK trade accounted for a fifth of Japan's total trade. Removing Hong Kong from the equation left China with 16.5% of trade, and the US with 18.5%. Japan's hollowing out shifting manufacturing operations to cheaper China partly explained the rise in Sino-Japanese trade, analysts said.