This method is sometimes called the rational or ad valorem method.
I trust the tariff of Heaven has an ad valorem scale for them—and all of us.
There is an ad valorem duty of 8% on imports and of about 1% on exports.
Ad valorem is a Latin phrase, signifying according to the value.
Down to the year 1834 the duty was an ad valorem one of 96 per cent.
The enumerated articles ...