They were crowded so close together that there was never any standing room and often not even sitting room. Again, they had to be supervised closely as many tried to starve themselves to death or to jump overboard. However, the greatest loss of slave property was due to disease, The ship's captain feared that disease would whittle away his profits, and, even more, he worried that it would attack him and his crew. When the passage was completed, and the West Indies had been safely reached, the slave again had to undergo the same kind of degrading inspection and sale which had occurred in Africa, but this time he had to experience the torment in a strange and distant land. While the economic profits in the slave trade were great, so were the human losses.
Statistics concerning the slave trade are often inaccurate or missing.
However, it is generally agreed that at least fifteen million Africans, and perhaps many more, became slaves in the New World. About nine hundred thousand were brought in the sixteenth century, three million in the seventeenth century, seven million in the eighteenth century, and another four million in the nineteenth century. The mortality rate among these new slaves ran very high. It is estimated that some five percent died in Africa on the way to the coast, another thirteen percent in transit to the West Indies, and still another thirty percent during the three-month seasoning period in the West Indies. This meant that about fifty percent of those originally captured in Africa died either in transit or while being prepared for servitude.