At the top of the list is north-western Europe with 1.91 billion tons of imports
and exports, followed by the United States with 1.31 billion tons, the Middle East with
1.23 billion tons and China with 0.998 billion. Moving to the bottom of the list, we find
some countries with very little trade, for example Cyprus with 6.7 mt and Brunei with
1.9 mt. To explain these trade volumes in a general way is difficult enough, but to do it
well enough to forecast their future trade flows is a daunting task. Clearly a short cut is
needed. We must look for a theory which will allow us to generalize about the factors
which determine a country’s trade. Armed with this theory, we can reduce the task
to more manageable proportions. The starting point is to see how trade relates to the
country’s general economic structure, and for this purpose three economic indicators
are shown in the table, land area (measured in thousands of hectares), population (measured
in millions) and GDP (measured in billions of dollars). The final columns show
three important ratios: population density, sea trade volume per capita and the trade per
million dollars of GDP. In the following paragraphs we will examine each of these
variables – the balance of trade, the size of the region, its level of economic activity, and
of course its trade intensity – to draw some general conclusions about what determines
the volume of sea trade.