There were almost 700 thousand slaves in the US in 1790, which equated to approximately 18 percent of the total population, or roughly one in every six people. By 1860, the final census taken before the American Civil War, there were four million slaves in the South, compared with less than 0.5 million free African Americans in all of the US. Of the 4.4 million African Americans in the US before the war, almost four million of these people were held as slaves; meaning that for all African Americans living in the US in 1860, there was an 89 percent* chance that they lived in slavery. A brief history Trans-Atlantic slavery began in the early sixteenth century, when the Portuguese and Spanish forcefully brought captured African slaves to the New World, in order to work for them. The British Empire introduced slavery to North America on a large scale, and the economy of the British colonies there depended on slave labor, particularly regarding cotton, sugar and tobacco output. In the seventeenth and eighteenth century the number of slaves being brought to the Americas increased exponentially, and at the time of American independence it was legal in all thirteen colonies. Although slavery became increasingly prohibited in the north, the number of slaves remained high during this time as they were simply relocated or sold from the north to the south. It is also important to remember that the children of slaves were also viewed as property, and (apart from some very rare cases) were born into a life of slavery. Abolition and the American Civil War In the years that followed independence, the Northern States began gradually prohibiting slavery, and it was officially abolished there by 1805, and the importation of slave labor was prohibited nationwide from 1808 (although both still existed in practice after this). Business owners in the Southern States however depended on slave labor in order to meet the demand of their rapidly expanding industries, and the issue of slavery continued to polarize American society in the decades to come. This culminated in the election of President Abraham Lincoln in 1860, who promised to prohibit slavery in the newly acquired territories to the west, leading to the American Civil War from 1861 to 1865. Although the Confederacy (south) were victorious in much of the early stages of the war, the strength in numbers of the northern states (including many free, black men), eventually resulted in a victory for the Union (north), and the nationwide abolishment of slavery with the Thirteenth Amendment in 1865. Legacy In total, an estimated twelve to thirteen million Africans were transported to the Americas as slaves, and this does not include the high number who did not survive the journey (which was as high as 23 percent in some years). In the 150 years since the abolishment of slavery in the US, the African-American community have continuously campaigned for equal rights and opportunities that were not afforded to them along with freedom. The most prominent themes have been the Civil Rights Movement, voter suppression, mass incarceration and the relationship between the police and the African-American community has taken the spotlight in recent years.

Worldwide, India was the country with the highest number of people living in modern slavery, either as forced laborers, sexual exploitation, forced marriages or other forms of coercion. An estimated 11 million people were living in modern slavery in India, followed by 5.8 million in China. This may come as no surprise as these are the two most populous countries worldwide. North Korea was the country with the highest number of people in modern slavery per 1,000 inhabitants.

Between 1501 and 1866, it is estimated that over 12.5 million people were forced onto ships in Africa, and transported to the Americas as slaves. Furthermore, it is estimated that only 10.7 million of these slaves disembarked on the other side of the Atlantic, meaning that roughly 1.8 million did not survive the journey. The transatlantic slave trade was a part of the triangular trade route between Europe, Africa and the Americas, during the sixteenth and nineteenth centuries. Generally speaking, this route saw European merchants bring manufactured products to Africa to trade for slaves, then transport the slaves to the Americas to harvest raw materials, before taking these materials back to Europe where they would then be consumed or used in manufacturing. Slavery was an integral part in funding the expansion of Europe's colonial empires, which shaped the modern and highly globalized world in which we live today.

The Middle Passage As with trade, the slave journey was also broken into three parts; the First Passage was the stage where slaves were captured and transported to African ports, the Middle Passage was the journey across the Atlantic, while the Final Passage was where the slaves were transported to their place of work. The death toll in the First Passage is thought to be the highest of the three stages, as millions were killed or fatally wounded as they were captured, however a lack of written data and historical evidence has made this number difficult to estimate. In contrast, shipping records from the time give a much more accurate picture of the Middle Passage's death toll, and this data suggest that roughly 14.5 percent of slaves did not survive the journey. The reason for this was the harsh and cramped conditions on board; slave ships were designed in such a way that they could fit the maximum number of slaves on board in order to maximize profits. These conditions then facilitated the spread of diseases, such as smallpox and dysentery, while malnutrition and thirst created further problems. Generally, slavers aimed to keep slaves as healthy (therefore; profitable) as possible, although there are countless examples of mistreatment and punishment of slaves by their captors, and several cases where slaves were exterminated by the crew as provisions ran low.

Rise and fall of the transatlantic slave trade

The European arrival in the Americas also saw the introduction of virgin soil epidemics (new diseases being introduced to biologically defenseless populations) which decimated the indigenous populations. The abundance of natural resources, but lack of available labor led to the rise of the transatlantic slave trade. Until the mid-1600s, Portuguese traders had a near-monopoly on this trade, supplying slaves to the newly expanding Spanish and Portuguese empires in South America. As other European powers began to expand their empires in the Caribbean and North America, the slave trade grew dramatically, and during the eighteenth century, the number of slaves being brought to the New World increased from an annual average of thirty thousand in the 1690s to 87 thousand in the 1790s. The transatlantic slave trade reached its peak between the 1750 and 1850, and an average of 74 thousand slaves were brought to the Americas each year between these dates. The largest decline came as the slave trade was disrupted during the American War of Independence (1775-1783), although the trade became weakened as the abolitionist movement gained momentum in Europe and the Americas around the turn of the century. The most significant impacts came as the slave trade was abolished in Britain and the U.S. in 1807 and Brazil in 1831, and Britain then used its position as the global superpower to impose abolition on other nations and used the Royal Navy to enforce these measures. While most nations abolished the slave trade in the early 1800s, it would take decades before the actual practice of slavery would be abolished; today, slavery is illegal in almost every country, however modern slavery in the forms of forced labor, human trafficking and sexual exploitation continues to be prevalent across the globe.

At the beginning of the 19th century, the U.S. labor force was approximately 1.9 million people, with slaves making up over half a million (28 percent) of this number. The share of slaves then increased to almost one third of the overall workforce in the next decade, but dropped to roughly one fifth by 1860; the year before the American Civil War. While the total number of slaves grew by several hundred thousand in each decade, their share of the U.S. labor force decreased due to the high levels of European migration to the U.S. throughout the 19th century. This wave of mass migration was an influential factor in slavery's eventual abolition, as Europeans met the labor demands that had previously been fulfilled by slaves, and those fleeing persecution and oppression in Europe were often sympathetic to the plight of slaves. Nonetheless, the majority of European migrants arrived in the industrialized, northern states, most of which had already abolished slavery in the 18th century, and slave labor was concentrated in the agricultural south at this time; this divide would prove fundamental in the outbreak of the American Civil War.

In Africa, Nigeria had the highest number of people living in modern slavery, with an estimated 1.6 million people. Ethiopia and Egypt followed in second and third with around 730,000 and 440,000 people. Meanwhile, Eritrea had the highest number in terms of victims per 1,000 inhabitants.

Throughout the history of the transatlantic slave trade, approximately 5.7 million of the 12.5 million African slaves who embarked on slave ships did so in ports along the region of West Central Africa and St. Helena. Today, these regions are in the countries of Angola, Democratic Republic of the Congo, Gabon, and the Republic of the Congo. The majority of the rest were taken from West Africa, embarking in ports between the present-day countries of Senegal and Gabon, while a smaller number of slaves were captured in the southeast of Africa. Senegambia and off-shore Atlantic islands had the highest number of captives taken from that region in the 16th century, however West Central Africa and St. Helena was the region where most slaves embarked on their journey across the Atlantic in the following centuries. As Portuguese traders were responsible for transporting the largest volume of slaves to the Americas, it is unsurprising that many of the busiest ports in the transatlantic slave trade were in Portuguese-controlled enclaves along the African coast.

This statistic shows the number of black men and women in the US from 1820 until 1880. Slavery was legal in the Southern States of the US until 1865, when the Thirteenth Amendment was added to the US Constitution after the American Civil War. Until that time all of the slaves included in this statistic were registered as living in the South, whereas the majority of the free, black men and women lived in the Northern States. From the data we can see that, while the slave experience was very different for men and women, there was relatively little difference between their numbers in each respective category. While female slaves were more likely to serve in domestic roles, they were also more likely to be working in the lowest and unskilled jobs on plantations, whereas men were given more skilled and physically demanding roles. As slavery was abolished in 1870, all black people from this point were considered free in the census data. It is also worth noticing that in these years the difference in the number of men and women increased, most likely as a result of all the black male soldiers who fell fighting in the American Civil War.

From 1501 until 1866, it is estimated that the transatlantic slave trade saw more than 12.5 million African people forcefully put on slave ships and transported to the Americas. Of these 12.5 million, only 10.7 million disembarked on the other side of the Atlantic, meaning that approximately 1.8 million (14.5 percent) did not survive the journey, known as the Middle Passage. Throughout most of the the sixteenth century, the mortality rate was around thirty percent, it then fell below twenty percent in the late seventeenth century, and below fifteen percent in the late eighteenth century. There was a slight increase in the mid-1800s, before the transatlantic slave trade effectively ended in the 1860s. The overall average mortality rate is lower than the rate in most decades, due to the larger numbers of captives transported in the late 1700s; a significant number of these voyages were between Africa and Brazil, which was generally the shortest of the major routes.

From the sixteenth to the mid-nineteenth centuries, Portuguese and Brazilian traders were responsible for transporting the highest volume of slaves during the transatlantic slave trade. It is estimated that, of the 12.5 million African slaves captured during this time, more than 5.8 million were transported in ships that sailed under the Portuguese and, later, Brazilian flags. British traders transported the second-highest volume of slaves across the Atlantic, totaling at almost 3.3 million; over 2.5 million of these were transported in the 18th century, which was the highest volume of slaves transported by one nation in one century.

Norway and Switzerland were the two countries in the world with the lowest prevalence of modern slavery. In the two European countries, only 0.5 people per 1,000 inhabitants were living in modern slavery. Denmark, Germany, the Netherlands, and Sweden followed with 0.6. On the other hand, North Korea had the highest prevalence at 104.6 per 1,000 population.

Eritrea was by far the country in Africa with the highest prevalence of modern slavery in 2021. An estimated 90.3 people per 1,000 inhabitants lived in modern slavery in the East African country. Mauritania followed behind with 32. On the other hand, Mauritius had the lowest prevalence at 1.5 per 1,000 population.

Between 1628 and 1860, it is estimated that almost 390 thousand Africans were transported as slaves to European colonies in Mainland North America. This figure refers only to those who survived the journey, as it is also thought that over 470 thousand captives embarked on these ships at African ports, however 84 thousand died en route (giving a mortality rate of 17.7 percent). The transportation of African slaves to the Thirteen Colonies was highest in the mid-18th century (although there was some fluctuation), before an observable decline around the time of the American Revolutionary War. Following independence, the importation of slaves remained lower than in previous decades, until it saw a sharp increase in the five years leading up to the slave trade's abolition. In 1807 alone, the year before the U.S. abolished the slave trade, almost 29 thousand slaves were imported from Africa into the U.S. Following this, activity declined greatly; the relatively small number of slaves imported from Africa to the U.S. were most likely into the Spanish territory of Florida. Smuggling also existed on a smaller scale; this accounts for the entries in 1858 and 1860.

From the time of Columbus' arrival on the island in 1494, until British annexation in 1655, the island of Jamaica was largely under Spanish control. During this time, Jamaica was not colonized as extensively as other areas of the Americas (due to the lack of precious metals, which had become the focus of Spanish expansion in the 16th) and was mostly used as a supply base for other colonization efforts. Because of this, the number of slaves brought to the island was relatively low, until Britain took control of the island and began planting on a much larger scale. Jamaica as the world's largest sugar exporter For most of the 18th century, Jamaica was Britain's most valuable colony in the Caribbean, as the British plantations focused largely on the production of cash crops; especially sugar. In the 1700s, Jamaica was the second largest sugar exporter in the world, behind the French colony of St. Domingue (Haiti); however, Haiti lost this position during the Haitian Revolution of the 1790s, at which point Jamaica emerged as the global leader. Jamaica held this title for almost three decades until the slave trade and slavery were abolished throughout the British Empire in 1807 and 1833 respectively, during which time which point Cuba quickly overtook it as the global leader. Demographic impact The vast majority of Jamaica's population at this time were African-born slaves or their ancestors; the high mortality rates and low fertility rates on Jamaica's plantations meant that slave owners had to import a high number of African captives into the colony in order to meet the output levels demanded by European consumers. There were sizeable numbers of white indentured servants, white planters, free people of color and maroons (former slaves who escaped and formed their own communities in Jamaica's interior) living in Jamaica during this century, however enslaved people made up the vast majority of Jamaica's population. Between 1607 and 1842, an estimated 1.02 million African captives disembarked in Jamaican ports, while an unknown number of slaves were imported from other areas of the Americas. The slave trade was abolished in 1807, yet the practice of slavery was not abolished until 1833 (and came into effect the following year); although no slave arrivals were recorded in these years, it is very likely that slaves continued to be smuggled into Jamaica until the mid-1800s. Today, it is estimated that approximately 98% of Jamaica's population is of African or mixed descent, the primary reason for this was the Atlantic slave trade.

The Middle East is one of the most vulnerable regions to modern slavery. Among the Middle Eastern states, the three countries with the largest share of at least 20 people for every 1,000 individuals living in modern slavery were from Saudi Arabia in the Gulf Cooperation Council (GCC).At the same time, Oman had the lowest levels of slavery among GCC countries, respectively. Jordan, on the other hand, had the highest share of individuals living in slavery among non-GCC countries. Modern-day slavery There are many forms of forced labor worldwide, with victims numbering in the millions. Organizations such as the International Labour Organization have been at the forefront of addressing the challenges of slavery in the 21st century. The response from governments towards modern slavery has been varied, with some states taking stronger action than others. Countries such as those in the GCC, which are dependent on a large immigrant workforce, are often more susceptible to worker exploitation. Global scrutiny on working conditions in the GCC Although contemporary slavery has been a major issue affecting many Arab and Gulf nations, the response of Arab states towards modern slavery shows that efforts are being made to address the issue. The rise in globalization, the goal of Arab states to diversify their economies and attract more foreign visitors, has put the treatment of their largely foreign labor force under increased scrutiny. A prime example was the FIFA World Cup hosted in Qatar in 2022, which put a spotlight on the conditions of employees working on some mega projects related to the event. Likewise, Saudi Arabia has increasingly been hosting international sporting and entertainment events, which have been the center of much debate from both domestic and foreign observers. This has compelled states to enact policies to ensure a more comprehensive oversight of labor protections and worker rights.

In the Americas, the United States and Brazil were the two countries with the highest number of people living in modern slavery. Around 1.1 million people were living in modern slavery in each of these countries. Worldwide, India was the country with the highest number of people in modern slavery.

According to records regarding the White House (i.e. census data and purchase or rental contracts), at least 201 slaves were known to have been hired from their owner to help build the White House and Capitol Building between 1792 and 1800. The source details that many slaves involved in this feat were undocumented, therefore the number of slaves who actually took part was likely much higher. Similarly, records also show that there were a number of slaves recorded as living or working on the White House grounds until 1850, during the tenure of ten of the first twelve U.S. presidents. It is important to note, however, that these figures apply only to the slaves who moved with the president to the White House (or were hired from their respective owner), and this data is not reflective of the number of slaves owned by U.S. presidents throughout their lifetimes.

Of these first twelve presidents, John Adams and William Henry Harrison were the only to not have slaves living with them in the White House, although Harrison was an advocate of slavery and was a slave owner during his lifetime. Adams' son, John Quincy Adams, also held a strong anti-slavery stance throughout his political career, however, when John Quincy's sister-in-law and brother-in-law died in 1813 and 1815 respectively, their four children went to stay in the White House and brought with them a small number of slaves.

An estimated 50 million people were living in modern slavery worldwide as of 2021. Nearly 30 million of these are found in Asia and the Pacific, which also is the most populous region in the world. North Korea was the country with the highest number of people in modern slavery per 1,000 inhabitants.

Russia was the country in Europe and Central Asia with the highest number of people living in modern slavery in 2021. Approximately 1.9 million people were living in modern slavery in the country. Türkiye and Ukraine had the second and third largest number of people in modern slavery. Meanwhile, the prevalence was highest in Türkiye.

North Korea was the country in the world with the highest number of people in modern slavery per 1,000 inhabitants. An estimated 104.6 people per 1,000 inhabitants were living in modern slavery in the Asian country. Eritrea followed behind with 90, whereas third placed Mauritania's number was significantly lower at 32 per 1,000 population.

Between 1775 and 1841, the population of Cuba grew to almost six times its size, from approximately 170 thousand people to over one million. During these years, Cuba was a Spanish colony, where slavery remained legal. In 1841, slaves counted for almost 45% of the total population.

Sugar industry A large reason for this growth was the emergence of the sugar industry, as production was relocated from areas of the Caribbean where slavery was abolished (most notably Haiti in 1804 and Jamaica in 1834). Although Cuba had been a Spanish colony for almost three centuries before these figures begin, it was economically isolated and trade with other nations was restricted; following a brief occupation by the British in the 1860s, international trade became encouraged, and a slave-based plantation complex emerged. By the middle of the 19th century, Cuba had established itself as the largest producer of sugar in the world (a position that it held until the mid-20th century), with the U.S. as it's primary consumer.

Gender differences From the figures for 1827 and 1841, the disparities between the male and female populations become apparent. Males migrated to the Americas at a much higher rate than females, while African males were also captured and enslaved at a higher rate than females during the Atlantic slave trade. This is reflected in the slave and white populations, although the difference within the slave population is much greater. Conversely, among free people of color, the female population population is actually higher than the number of males; this was due to a number of reasons, such as higher rates of manumission among females (the ratio of female to male manumissions was estimated to be around 3:2 in the Caribbean in the 19th century) and higher life expectancy.