A land of vast distances and rich natural resources, Canada became a self-governing dominion in 1867 while retaining ties to the British crown. Economically and technologically the nation has developed in parallel with the US, its neighbor to the south across an unfortified border. As an affluent, high-tech industrial society in the trillion-dollar class, Canada resembles the US in its market-oriented economic system, pattern of production, and affluent living standards. Since World War II, the impressive growth of the manufacturing, mining, and service sectors has transformed the nation from a largely rural economy into one primarily industrial and urban. Top-notch fiscal management has produced consecutive balanced budgets since 1997, although public debate continues over the equitable distribution of federal funds to the Canadian provinces. Exports account for roughly a third of GDP. Canada enjoys a substantial trade surplus with its principal trading partner, the US, which absorbs 80% of Canadian exports each year. Canada is the US's largest foreign supplier of energy, including oil, gas, uranium, and electric power. During 2007, Canada enjoyed good economic growth, moderate inflation, and the lowest unemployment rate in more than three decades.