Understand how the writer sees the degree of contribution of an item to variations in the volume of exports and imports

Goal

To be able to understand how the writer sees the extent of the contribution of an item to variations in the volume of exports and imports.

Setting

You are reading the part of a White Paper on International Economy and Trade where the trends in Japan's trading activities are described. Read a passage about trends in trading activities categorized by item and understand how the writer sees the extent of the contribution of an item to variations in the volume of exports and imports.