Straits dollar. Different notes were issued by the Sarawak Government Treasury, the earliest notes using English, Jawi and Chinese characters. From the 1880s, the notes' background featured the Rajah's portrait and coat of arms. Society Demography In 1841, Sarawak had an indigenous population of about 8,000. The Dayaks were the largest indigenous group in the interior: comprising Iban, Bidayuh and other interior tribes such as the Kayan, Kelabit, Kenyah, Lun Bawang and Penan, while coastal areas were dominated by the Sarawak local Malays, Melanau, Bruneian and Kedayan. The government of Sarawak welcomed the migration of Chinese workers to boost the economy. Following various immigration schemes initiated by the Rajahs, the population increased to 150,000 in 1848, 300,000 in 1893, 475,000 in 1933, and 600,000 in 1945. Water transport It was during the reign of the Second Rajah that public infrastructure began to be given attention. The river systems in Sarawak are not inter-connected. As a result, coastal ships were used by the Brooke government to carry merchandise from one river system to another. The Brooke government also established a trade route from Kuching to Singapore, using its own ships such as The Royalist, Julia, and The Swift. Among the early cargoes were antimony and gold. The Borneo Company Limited bought another steamer, which they named the Sir James Brooke, to carry antimony, coal, and sago. The ships were the link between Sarawak and Singapore. Charles Brooke encouraged the Sarawak Chamber of Commerce to set up its own shipping lane to Singapore, offering to sell The Royalist to it. In 1875, the "Singapore and Sarawak Steamship Company" was formed and, shortly thereafter, bought The Royalist and the steamer The Rajah Brooke. There were complaints that the company provided irregular services to its customers and, in 1908, the Brooke government transferred another two small steamships, the Adeh and Kaka, to the company in expectation of improvement. In 1919, Chinese interests bought the company's shares, liquidated it and formed a new company named the "Sarawak Steamship Company". The company established shipping lanes linking the Rajang, Limbang, and Baram river systems. The Sibu-Singapore shipping lane was started by the company but soon abandoned, being unprofitable. The establishment of the shipping lanes by Sarawak Steamship Company allowed the indigenous people to participate in wider markets, thus narrowing the income gap between urban and rural areas in Sarawak. The company suffered heavy losses in the trade