In achieving this result, the plantations were expected to play an important part; and no one doubted that they had done so. During the decade after the Restoration, the commerce between England and her American possessions was about one tenth of her total foreign trade; in 1700 it was about one seventh. Imports from the colonies rose from L500,000 to more than L1,000,000, and exports to the colonies from L105,910 to L750,000. But the mere increase of trade was no perfect index of the importance of the plantations; for the colonial trade built up the merchant marine far more, in proportion to its volume, than any other. The American voyages were long; plantation commodities bulked large in proportion to their value; and whereas much of the commerce between England and Europe was carried in foreign ships, colonial trade was confined to British vessels. If, therefore, the merchant marine more than doubled during the Restoration, that happy result was thought to be largely due to the colonies. "The Plantacion trade is one of the greatest nurseries of the Shipping and Seamen of this Kingdome, and one of the greatest branches of its trade," said the customs commissioners in 1678; "the Plantacions, New Castle trade, and the fisheries, make 3/4 of all the seamen in ye Nation." The colonies which enlisted the enthusiasm of the commissioners were the plantations proper. There were men, such as Charles Davenant, who thought New England might have its uses; but the high value of Maryland and Virginia, of Barbados and Jamaica, was obvious to all. Maryland and Virginia, it is true, were not quite ideal colonies, since it was found necessary, in their interest, to prohibit the raising of tobacco in England. But the sugar islands were without reproach. England was not now, as in the time of James I, thought to be overpopulated; and Barbados and Jamaica found favor, not only because their products were neither raised nor made in England, but because they could be exploited by slave labor. It was pointed out that happily "by taking off one useless person, for such generally go abroad [to the islands], we add Twenty Blacks to the Labour and Manufactures of the Nation." Negroes procured in Africa at slight cost might, indeed, be counted as commodities of export, while the island colonies cultivated precisely those commodities which England would otherwise have imported from foreign countries. And the statistics of the custom-house confirmed the theory of the pamphleteer; in 1697, seven eighths of all colonial commerce was with the tobacco and sugar plantations, and Jamaica alone offered a greater market than all the Northern and Middle colonies combined.