of Australia feared being demographically overwhelmed by the heavily populated Asian countries to the north. Following the attacks on Darwin and the associated fear of Imperial Japanese invasion in WWII, Minister of Immigration Arthur Calwell stated in 1947: "We have 25 years at most to populate this country before the yellow races are down on us." This concern about Australia's demographic vulnerability was a driving force behind the country's massive post-war program of European immigration. Post-war immigration After World War II, Australia believed that it must increase its population to avoid the threat of another invasion and launched an immigration program whose goal was to increase Australia's population with the slogan "populate or perish". Hundreds of thousands of displaced Europeans immigrated to Australia with more than three million people immigrating from Europe during the late 1940s until the 1960s. The Immigration Minister, Arthur Calwell, introduced the Assisted Passage Migration Scheme in 1945. The government was still trying to increase Australia's population, especially with people who have skills in the secondary industry sector. As the world was transforming into a more industrial and technological world, Australia needed to keep up. Australia looked first to Britain for migrants. In the beginning the assisted immigration scheme was popular among young married couples and single people. It was inexpensive, an adventure and an opportunity. After only a year, however, there was a shortage of ships and numbers dropped. The immigration targets were not being met. For the first time, in a revolutionary step for both Australian society and international relations, Australia looked outside Britain for migrants. In 1947, Calwell agreed to bring 12,000 people every year from Estonia, Latvia, Lithuania, and Poland. Many of these people were refugees who were being cared for by the International Refugee Organisation (IRO). They were accepted on humanitarian grounds with the condition that they would remain in Australia for two years and work in government selected jobs. 182,159 people were sponsored by the IRO from the end of World War II up to the end of 1954 to resettle in Australia from Europe. Over the next twenty years, patterns of immigration continued to change. The government encouraged more people to come to Australia and many more assisted agreements were made with countries. In the late 1950s, more immigrants began to be accepted from the Middle East. In 1958, under the Migration Act 1958, the dictation test was removed