In 2008, Canadian exports to the United States and Mexico were at $381.3 billion, with imports at $245.1 billion. According to a 2004 article by University of Toronto economist Daniel Trefler, NAFTA produced a significant net benefit to Canada in 2003, with long-term productivity increasing by up to 15 percent in industries that experienced the deepest tariff cuts. While the contraction of low-productivity plants reduced employment (up to 12 percent of existing positions), these job losses lasted less than a decade; overall, unemployment in Canada has fallen since the passage of the act. Commenting on this trade-off, Trefler said that the critical question in trade policy is to understand "how freer trade can be implemented in an industrialized economy in a way that recognizes both the long-run gains and the short-term adjustment costs borne by workers and others".