The compilation of GDP requires a large amount of data, including production, sales, consumption, investment, and external trade data. Because of the country's small size and the fact that inter-city and inter-county production and consumption are commonplace, collecting basic data for individual cities and counties would be extremely difficult. As a consequence, in view of DGBAS' limited resources and manpower, and weighing the country's overall administrative priorities and actual needs, DGBAS does not compile the GDP by the county and city.