In cases where the number of exporters, producers, importers or types of products involved is so large as to make such a determination impracticable, the authorities may limit their examination either to a reasonable number of interested parties or products by using samples which are statistically valid on the basis of information available to the authorities at the time of the selection, or to the largest percentage of the volume of the exports from the country in question which can reasonably be investigated.
In cases where the number of exporters, producers, importers or types of products involved is so large as to make such a determination impracticable, the authorities may limit their examination either to a reasonable number of interested parties or products by using samples which are statistically valid on the basis of information available to the authorities at the time of the selection, or to the largest percentage of the volume of the exports from the country in question which can reasonably be investigated.