former German settlements into Japanese boom towns. The initial population figures (1919-1920) for the mandated territories included around 50,000 islanders, made up from the indigenous peoples of Oceania. Japanese immigration led to the population growing from under 4,000 in 1920 to 70,000 inhabitants in 1930, and more than 80,000 in 1933. By 1935 the Japanese population alone was more than 50,000. By 1937 almost 90 percent of the population on Saipan was Japanese (42,547 out of 46,748). In the census of December 1939, the total population was 129,104, of which 77,257 were Japanese (including ethnic Chinese and Koreans), 51,723 indigenous islanders and 124 foreigners. While the settler population was growing, the indigenous Micronesian population in some areas was declining. The rights and status of the indigenous population differed from those of Japanese imperial subjects. Employment prospects for Micronesians were more restricted, with unequal labor conditions and pay. The government of the Mandate built and maintained hospitals and schools, and free education was provided for Micronesian children aged 8–15. However, Micronesian children attended separate schools from those used by Japanese children, and the schooling provided in them was more limited and of shorter duration. Micronesian children often attended boarding schools where compulsory schooling was used to promote Japanese state religion and Shinto rituals. A Shinto shrine known as the Nan'yō Shrine was established on Koror in 1940. Christian mission schools were prohibited from taking Micronesian pupils where government schools existed. Economy Japanese economic involvement in Micronesia began in the late 19th century. Before the establishment of the Mandate, small groups of Japanese entrepreneurs established commercial ventures in German Micronesia and came to control a significant proportion of the trade. However, the economic development of the area was hampered by the distances separating the islands, their small land areas and their small market sizes. The mandate was initially a financial liability for the Japanese government, requiring an annual subsidy from Tokyo. The cash crop of the islands was copra, which was used in many commercial products at the time. During the 1920s and 1930s, the Japanese government pursued a policy of encouraging monopolies that paired private initiative with government capital. This strategy was intended to maximise the number of Japanese colonists. Until the late 1930s, the development of the islands was undertaken primarily to assist the Japanese civilian economy. Sugar cane had become increasingly sought-after in Japan, and Japanese trading companies led