Chinese settlers began migrating from the Riau Islands to Singapore in the 19th century shortly before the founding of Singapore by Sir Stamford Raffles in 1819. The native Malays joined the Chinese in growing gambier, although they cultivated it for subsistence rather than for commercial purposes. The number of gambier and pepper farms expanded greatly between 1819 and 1840, fuelled by the increasing demand for gambier by Chinese traders from China as well as pepper by European traders. As land nearer to the town in the south was quickly used up in the 1820s, the Kangchu began to establish farms near the northern parts of Singapore, particularly stretches of land across the Straits of Johor from Jurong, to the west of Punggol in the northeast. By 1851, there were about 800 gambier and pepper farms which covered 75% of Singapore's land surface, of which was dedicated to gambier while 2,614 was dedicated to pepper.