Availability of Data in the NBER World Trade Data Base For the great majority of countries or other entities listed, the data base covers all years from 1962 to 2000. There are exceptions, however, noted in the following table, which is arranged in the numerical order of the country codes, starting with 100000, World. Some of the Not Elsewhere Specified classifications appear and disappear as countries appear and disappear in partner country classifications. Some of the countries were not in existence as countries at the beginning of the period (e.g. Malawi, Rwanda). Others did not begin reporting to the UN for some time after establishment or other political changes (e.g, the Russian Federation), or interrupted their reporting (e.g., United Arab Emirates). A few countries had not reported data for 2000 at the time the later trade data were purchased from the UN (e.g., India).