Basically here we are talking about the demand for sea transport otherwise known as ships as well as the supply of these ships. NB: ships and vessels will be used interchangeably.
.
* Overview * Value of volume of world trade by sea * It is difficult to quantify the value of volume of world seaborne trade in monetary terms, as figures for trade estimates are traditionally in terms of tonnes or tonne-miles, and are therefore not comparable with monetary-based statistics for the value of the world economy. * However, the United Nations Conference on Trade and Development (UNCTAD) estimates that the operation of merchant ships contributes about US$380 billion in freight rates within the global economy, equivalent to about 5% of total world trade. * Shipping trade estimates are often calculated in tonne-miles, as a way of measuring the volume of trade (or "transportation work ", as it is sometimes referred). In 2008, for example, it is estimated that the industry transported over 7.7 thousand million tonnes of cargo, equivalent to a total volume of world trade by sea of over 32 thousand billion tonne-miles. * World seaborne trade 1969-2010 *
Source: Fearnley's Review * Throughout the last century the shipping industry has seen a general trend of increases in total trade volume. Increasing industrialisation and the liberalisation of national economies have fuelled free trade and a growing demand for consumer products. Advances in technology have also made shipping an increasingly efficient and swift method of transportation. Over the last four decades total seaborne trade estimates