The only difference between a tariff surcharge and a tariff was that the rate of the surcharge could be changed by administrative decree, whereas tariff rates could be altered only by an act of the legislature. Under this measure, domestic dairy processors were permitted to import material inputs (such as skimmed milk powder) only after they have absorbed all domestically produced milk. When first introduced the ratio was 1:25, which means that for every 1 litre of domestic production that is absorbed, processors were permitted to import 25 litres of milk (or milk equivalent), indicating that the local content was only 4%. The ratio was gradually strengthened over time and was 1:1.7 for the second half of 1997 just prior to its removal.