Big slate of refinery maintenance in U.S., Canada; export rush bucks long-term trend. A late-year rush for gasoline in the United States is creating unexpected demand for imported cargoes and giving struggling European refineries a welcome autumn boost. An extensive slate of refinery maintenance on the U.S. Gulf Coast and in Canada has sapped gasoline availability, leading to a 70-percent increase in cargoes sailing west from Europe this month over levels in August - usually the time of peak demand. "What we're seeing now is not normal," one trader said. "The strength in the United States is dramatic. Traders said the U.S. shortage could get worse as demand in West Africa and the Middle East is also now attracting European cargoes. The pull bucks a trend of lower U.S.