The issuer of a written origin declaration must, in addition to other supporting documents, be considered originating to prove the originating status of the goods, for a period of five years from the date of importation of the goods for the goods going into Canada and for a period of ten years from the date of importation of the goods for the goods, Who go to Mexico, have at their disposal. NAFTA came into force in 1994 under the Clinton administration. The objective of the agreement was to stimulate trade in North America between Canada, the United States and Mexico. The aim was also to reduce trade barriers between the three sides as well as most taxes and customs duties on products imported and exported by both sides. Supporters supported NAFTA because it opened Up Mexican markets to U.S. companies like never before. In the past, the issue of Canada`s major trading partners and dependence on certain markets has been an important political issue. At the time of Confederation in 1867, the United Kingdom was by far Canada`s largest trading partner, reflecting the close historical, cultural and institutional ties within the British Empire. Over time, more and more Canadian businesses have been carried out proportionally with the United States. Several governments hoped to strengthen or reverse this trend by changing customs policy either in favour of imperial preference with the British or reciprocity with the national policy of internal development. The elections of 1891 and 1911 were held in part on the issue of closer trade relations with the British. After the Civil War, the United States became Canada`s largest trading partner.