Under Mughal rule, Bengal was a center of the worldwide muslin and silk trades. During the Mughal era, the most important center of cotton production was Bengal, particularly around its capital city of Dhaka, leading to muslin being called "daka" in distant markets such as Central Asia. Domestically, much of India depended on Bengali products such as rice, silks and cotton textiles. Overseas, Europeans depended on Bengali products such as cotton textiles, silks and opium; Bengal accounted for 40% of Dutch imports from Asia, for example, including more than 50% of textiles and around 80% of silks. From Bengal, saltpetre was also shipped to Europe, opium was sold in Indonesia, raw silk was exported to Japan and the Netherlands, cotton and silk textiles were exported to Europe, Indonesia, and Japan, cotton cloth was exported to the Americas and the Indian Ocean. Bengal also had a large shipbuilding industry. Economic historian Indrajit Ray estimates shipbuilding output of Bengal during the sixteenth and seventeenth centuries at 223,250 tons annually, compared with 23,061 tons produced in nineteen colonies in North America from 1769 to 1771.