Were 80 million black slaves killed in the USA by the end of the civil war?

Question

I was listening to a speech by Malcolm X, where he said (at 1:57) that over 80 million black people were killed in America (100 million brought over as slaves, but less than 20 million remained at the end of the civil war).

You haven't got no time to cry for no Jew, cry for yourself. Let him solve his problem and you solve your problem. Why, they only killed 6 million Jews. Only 6 million Jews were killed by Hitler. Uncle Sam killed 100 million black people, bringin' em here, yeah. 100 million! 100 million! Don't let no Jew get up in your face and make you cry for him. ... 100 million black people were taken from Africa, and when the Civil War was over there weren't 6 million black people in America. There weren't 20 million black people in the western hemisphere. What happen to 80 million? Where did they go? Where did they disappear? Why, that dog dropped 'em in the water and worked them to death. He murdered them! He butchered them! He mutilated them! I mean 80 million of your and my forefathers. ... 80 million black people dead, murdered, and these Jews got the audacity to run around here and want you to cry for them.

But this figure seems like an exaggeration: According to PBS (quoting the Trans-Atlantic Slave Trade Database) around 13 million African slaves were brought to the New World between 1525 and 1866, and less than 400,000 were brought to North America. Even allowing for some significant error, those numbers are different by orders of magnitude.

Was Malcolm X's number accurate?

Answer 1

Dwight Lowell Dumond's Antislavery ¹ is available at archive.org. The quote about 100 million is on the first page of chapter 7 and does not give a reference for that figure.

SlaveVoyages, a database that is the result of years of international research, has statistics and specific information on individual ships involved in the transatlantic slave trade based on records from the ships themselves. For some of the later ships, the names of the enslaved persons were recorded and are available in the database.

According to this database, approximately 10.7M enslaved persons embarked from Africa. Of these, only 9.2M disembarked, a mortality rate of 12% from the voyage alone. 50% went to the Caribbean, 35% to Brazil, about 10% to mainland North America and Spanish mainland Americas, and the remaining 5% to Europe and other destinations.

At first glance, looking at the ~10 million figure given for the number of Africans removed across the Atlantic, the 100 million figure would appear to be off by a factor of 10. However, look again at the Dumond quote:

The denial of emancipation by conversion to Christianity had shifted the basis of slavery from heathenism to race. The consequences were frightful. It unloosed on Africa for generations a terror unequaled in human history--a terror that did not cease until 100 million human beings perished.

Although the chapter opens with a sentence about "slavery in the United States," this particular quoted passage is referring to the effect on Africa and Africans -- for generations, not specifically those who were explicitly transported against their will to the United States, but all of those who were removed from Africa and their enslaved descendants.

Also, the quote does not say that 100 million were transported; it says that 100 million perished. This number includes the ~10 million forcibly removed from Africa and taken to any destination over 350 years, plus all of their descendants who died while enslaved.

We probably cannot follow all of the enslaved persons to all of their destinations, so as a proxy, let us look at the numbers for the United States.

Enslaved persons were enumerated in the United States census between 1790 and 1860. The aggregate numbers are available from census.gov.

Census Year	Enslaved Persons (in thousands)
1790	698
1800	893
1810	1191
1820	1538
1830	2009
1840	2487
1850	3204
1860	3951

These figures are only snapshots in time; they don't give us a total number over time. However, it is likely that none of the 698,000 persons enumerated in the 1790 census were still alive for the 1860 census. Also, note that slavery had existed in mainland North America for 171 years before the first census.

According to SlaveVoyages, 365,713 people were taken from Africa to mainland North America between 1655 and 1860 (1619-1654 were from intra-American voyages). The number of enslaved persons in the 1860 U.S. census, 3,951,531, is a little more than 10 times the number who were removed from Africa and taken to mainland North America.

There was some intra-American trade in enslaved persons, about 450,000 according to SlaveVoyages, and the sugar plantations of the Caribbean are known to have been especially deadly, but let us assume anyway that the 10x ratio of transported Africans to final number of enslaved persons applies everywhere.

Using that 10x ratio, it is conceivable that the approximately 10 million Africans removed over 350 years could have resulted in a population of 100 million enslaved persons, hence 100 million deaths, across the Caribbean, Brazil, mainland North America, Spanish mainland Americas, and other locations.

Thus, it seems that Dumond's figure of 100 million deaths over 350 years across the entire Americas region may be accurate, but it was misinterpreted by Malcolm X to be the number of Africans uprooted from their continent and further misinterpreted by others as the number of Africans brought to the United States.

¹_{The hyphen appears only on the front cover. On the title page and the numbered pages, the title is not hyphenated.}

Answer 2

In my hunt for the transcript of this video, I stumbled upon the following quote from The Black Revolution (April 8, 1964) regarding the source for his claim:

One hundred million Africans were uprooted from the African continent—where are they today? One hundred million Africans were uprooted, 100 million Africans, according to the book Anti-Slavery, by Professor Dwight Lowell Dumond—excuse me for raising my voice—were uprooted from the continent of Africa. At the end of slavery you didn’t have 25 million Africans in the Western Hemisphere.

So regardless of the (potential) dispute with the database, his source is Anti-Slavery--that is to say, not an exaggeration.

Indeed, this book says on page 63:

The denial of emancipation by conversion to Christianity had shifted the basis of slavery from heathenism to race. The consequences were frightful. It unloosed on Africa for generations a terror unequaled in human history--a terror that did not cease until 100 million human beings perished.