The size of the exodus increased during and after the war. The monthly number of boat people arriving in Southeast Asia increased to 11,000 during the first quarter of 1979, 28,000 by April, and 55,000 in June, while more than 90,000 fled by boat to China. In addition, the Vietnamese military also began expelling ethnic Hoa from Vietnamese-occupied Cambodia, leading to over 43,000 refugees of mostly Hoa descent fleeing overland to Thailand. By now, Vietnam was openly confiscating the properties and extorting money from fleeing refugees. In April 1979 alone, Hoa outside of Vietnam had remitted a total of US$242 million (an amount equivalent to half the total value of Vietnam's 1978 exports) through Hong Kong to Ho Chi Minh City to help their friends or family pay their way out of Vietnam. By June, money from refugees had replaced the coal industry as Vietnam's largest source of foreign exchange and was expected to reach as much as 3 billion in US dollars. By 1980, the refugee population in China reached 260,000, and the number of surviving boat people refugees in Southeast Asia reached 400,000. (An estimated 50% to 70% of Vietnamese and Chinese boat people perished at sea.)