Total trade maybe, but certainly not exports. Where are you getting your figures from? The US total exports are around $800 billion.
The $30-35 billion between Hong Kong and the PRC is about right for our 2002 combined exports.
Keep in mind though that between Taiwan and Japan, they import more than twice that much from the US.
With Korea included they import about 3 times as much as a combined Hong Kong-PRC alliance.
This is also with the rest of Asia in the economic funk. The PRC is booming by their own admission. When the rest of Asia recovers (still from 1998) combined, they will dwarf China's consumption of US exports.