The General Agreement on Trade in Services (GATS) is one of the World Trade Organization's most important agreements. This accord is the first and only set of multilateral rules covering international trade in services. It is a framework for international trade in services and a legal basis for resolving conflicting national interests. For the past two decades, trade in services has grown faster than merchandise trade. Currently, they represent more than two thirds of the World Gross Domestic Product. As the term services covers a wide range of intangible and heterogeneous products and activities, there has been an increasing demand for detailed, relevant and internationally comparable statistical information on trade in services. In the last ten years, the share of transportation services in international trade in commercial services was steady and amounted to about one quarter.