Transportation in Canada, the world's second-largest country in total area, is predicated on efficient, high-capacity multimodal transport spanning often vast distances between natural resource extraction sites, agricultural and urban areas. Canada's transportation system includes more than of roads, 10 major international airports, 300 smaller airports, of functioning railway track, and more than 300 commercial ports and harbours that provide access to the Pacific, Atlantic and Arctic oceans as well as the Great Lakes and the St. Lawrence Seaway. In 2005, the transportation sector made up 4.2% of Canada's GDP, compared to 3.7 or Canada's mining and oil and gas extraction industries.