1970s and early 1980s, the remaining sterling balances were wound down to a level that represented the significance of Britain in contemporary world trade. Purpose Before the First World War, the British pound sterling was the most important international currency, and the City of London was the world's most important financial centre. More than 60 per cent of global trade was financed, invoiced, and settled in sterling, and the largest proportion of official reserves, apart from gold, was held in sterling. Although not all the territories of the British Empire used sterling as their local currency, most of those that did not pegged their local currency at a fixed rate to sterling, as did many foreign countries outside the Empire. When Britain left the gold standard in 1931, many countries that had pegged their currencies to gold pegged their currencies to sterling instead; this group of countries became known as the "sterling bloc", though the term "sterling area" was used officially from at least 1935. When the Second World War broke out, the sterling bloc countries within the British Empire shared a desire to protect the external value of sterling; legislation was therefore passed throughout the Empire formalising the British sterling bloc countries into a single exchange control area. The sterling area was continued in the postwar era in an attempt to preserve the British Empire's superpower status during the Cold War between the United States and the Soviet Union. Canada and Newfoundland Canada and Newfoundland did not join the sterling area because their dollar currencies had effectively been linked to the US dollar until they were forced off the gold standard in 1931 along with Britain. But while Australia, New Zealand, and South Africa all responded to the end of the gold standard by pegging their pounds to the pound sterling, Canada and Newfoundland instead pegged their dollars to the US dollar. So Canada and Newfoundland did not stand to gain by joining an exchange control bloc intended to protect the external value of sterling. The absence of Canada and Newfoundland from the sterling area was beneficial to Britain, as it curtailed capital flight to the North American mainland. Canada nevertheless introduced its own exchange controls at the outbreak of war; these were maintained until 1953. Canada's exchange controls were 'sterling area-friendly', in that their purpose was more to prevent capital flight to the US than to prevent flight