"African immigration to North America dates back to the time of the first European arrivals. During the entire period of American colonial history, involuntary immigrants arrived as slaves from Africa, mainly West Africa. Between 1700 and 1775, an estimated 278,400 Africans reached the original thirteen colonies that became the United States. Slave importation to the coastal states of the South grew rapidly during the late seventeenth century and the first half of the eighteenth century because of the growth of the tobacco and rice economies. Imports of slaves to tobacco-growing Virginia reached 7,000 per decade for the 1670’s through the 1720’s and then nearly doubled to 13,500 per decade until the 1750’s. South Carolina, where rice had become an important crop, began importing slaves at about the same level as Virginia during the early eighteenth century and then increased to more than 20,000 during the 1720’s. While slave importation began to slow in Virginia during the later eighteenth century, it continued at about 17,000 per decade in South Carolina from the 1750’s to the 1790’s. By the time of the first U.S. Census in 1790, as a result of involuntary immigration and the increase of native-born slaves, people of African ancestry made up one-fifth of the American population."