On January 29, 2020, President Donald Trump signed the agreement between the United States, Mexico-Canada. Canada has not yet adopted it in its parliamentary body until January 2020. Mexico was the first country to ratify the agreement in 2019. NAFTA has had three major advantages. U.S. food prices were lower due to duty-free imports from Mexico. Oil imported from Canada and Mexico has prevented the rise in gas prices. NAFTA has also increased trade and economic growth for all three countries. In 2008, Canadian exports to the United States and Mexico were $381.3 billion, with imports of $245.1 billion.  According to a 2004 paper by University of Toronto economist Daniel Trefler, NAFTA provided Canada with a significant net benefit in 2003, with long-term productivity increasing by up to 15 per cent in the sectors that experienced the largest tariff reductions.  While the decline in low-productivity jobs has reduced employment (up to 12 per cent of existing jobs), these job losses have lasted less than a decade; Overall, unemployment has declined in Canada since the legislation was passed. Trefler commented on the compromise, saying that the crucial trade policy issue was « how free trade can be implemented in an industrialized economy so that the long-term benefits and short-term adjustment costs borne by workers and others are recognized. »  After diplomatic negotiations in 1990, the heads of state and government of the three nations signed the agreement on 17 December 1992 in their respective capitals. The signed agreement had to be ratified by each country`s legislative or parliamentary department. The free trade agreement was concluded in 1988 and NAFTA extended most of the provisions of the free trade agreement to Mexico. NAFTA was negotiated by the governments of U.S. President George H.W. Bush, Canadian Prime Minister Brian Mulroney and Mexican Prime Minister Carlos Salinas de Gortari. An interim agreement on the pact was reached in August 1992 and signed by the three heads of state and government on 17 December. NAFTA was ratified by the national parliaments of the three countries in 1993 and came into force on January 1, 1994. In 2015, the Congressional Research Service concluded that « NAFTA`s overall net impact on the U.S. economy appears to be relatively small, not least because trade with Canada and Mexico accounts for a small percentage of U.S. GDP.