. "Ad valorem means \"in proportion to the value.\" It is used in relation to duties on imports that are fixed at a percentage of the value as stated on the invoice."@en . "Ad valorem"@ia . "Ad valorem means \"in proportion to the value.\" It is used in relation to duties on imports that are fixed at a percentage of the value as stated on the invoice."@en . . "Ad valorem"@en . . .