Trade volume indices, by reporting country

Volume index = value index / unit-value index Value index: The value index is calculated as the percentage change between the trade value of the current month and the average monthly trade value of the previous year. Unit-value index: Monthly raw data are processed at the most detailed level in order to calculate elementary unit-values defined by trade value/quantity. These unit-values are divided by the average unit-value of the previous year to obtain elementary unit-value indices, from which outliers are detected and removed. Elementary unit-value indices are then aggregated over countries and commodities, by using the Laspeyres, Paasche and Fisher formulae. Finally, the Fisher unit-value indices are chained back to the reference year (2015 = 100).