During the 18th century, the Nawabs of Bengal became the region's "de facto" rulers. The title of the ruler is popularly known as the "Nawab of Bengal, Bihar, and Orissa", given that the Bengali Nawab's realm encompassed much of the eastern subcontinent. The Nawabs forged alliances with European colonial companies, which made the region relatively prosperous early in the century. Bengal accounted for 50% of the gross domestic product of the empire. The Bengali economy relied on textile manufacturing, shipbuilding, saltpetre production, craftsmanship, and agricultural produce. Bengal was a major hub for international trade – silk and cotton textiles from Bengal were worn in Europe, Japan, Indonesia, and Central Asia. Annual Bengali shipbuilding output was 223,250 tons, compared to an output of 23,061 tons in the nineteen colonies of North America. Bengali shipbuilding proved to be more advanced than European shipbuilding prior to the Industrial Revolution. The flush deck of Bengali rice ships was later replicated in European shipbuilding to replace the stepped deck design for ship hulls.