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.

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.

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.

The issue of race and slavery was arguably the largest cause of the American Civil War, with the southern states seceding from the Union as the practice of slavery became increasingly threatened. From the graph we can see that roughly 16.5 percent of the entire US population at this time was black, and the vast majority of these were slaves. In 1860 there were almost 27 million white people, four and a half million black people, and less than one hundred thousand non-black or white people (mostly of Native/Latin American or East-Asian origin).

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.

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.

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.

Knowledge regarding the prices paid for slaves during the transatlantic slave trade is quite scarce, however the data that does exist provides some insight into the financial value given to slaves during this period. The study shown here indicates that at certain intervals between 1638 and 1775, the average price paid for slaves in the Thirteen Colonies ranged from 16.5 to 44.08 pounds sterling for slaves from Britain's colonies in the Americas, and between 1.87 and 17.43 pounds for slaves transported from West Africa. It is important to note that the average prices given are from sample sizes of ranging between just one and 29 sales, therefore the numbers may be more reliable in some years than in others.

Despite these limitations, the data does show a clear difference between the prices for slaves who were born in the Americas or accustomed to its climate (known as "seasoned"), compared to those who had travelled from West Africa, as those were often weakened from the journey and susceptible to tropical disease, and therefore deemed less valuable. For example, in the period between 1713-17 (the group with the largest sample size), the average value of unseasoned slaves from West Africa was just 38.5% the value of seasoned slaves.

Throughout the transatlantic slave trade, approximately 2.3 million enslaved Africans disembarked in the British Caribbean between the 17th and early-19th centuries. Almost half of these slaves disembarked in Jamaica, which was Britain's most valuable and profitable possession in the Caribbean in these times. Barbados was the second most common destination for slaves disembarking in the British Caribbean, and it was the most common destination in the 17th century, due to the booming sugarcane industry that emerged in the 1640s. Several other islands saw the disembarking of more than one hundred thousand slaves, mostly along the Lesser Antilles in the 18th century, while British Guiana and other islands saw the arrivals of fewer slaves, although they still numbered in the tens of thousands. Almost eighty percent of all slave arrivals in the British Caribbean took place in the 1700s; the highest number of slaves disembarked in the British Caribbean in the final quarter of this century, as Britain sought to invest in and protect its colonies in the Americas, after the loss of its most profitable colony following the United States' declaration of independence in 1776 (although the subsequent Revolutionary War did greatly disrupt the transatlantic slave trade from1776 to 1783).

Lynching in the United States is estimated to have claimed over 4.7 thousand lives between 1882 and 1968, and just under 3.5 thousand of these victims were black. Today, lynching is more commonly associated with racial oppression, particularly in the south, however, in early years, victims were more commonly white (specifically Mexican), and lynchings were more frequent in western territories and along the southern border. It was only after Reconstruction's end where the lynching of black people became more prevalent, and was arguably the most violent tool of oppression used by white supremacists. Nationwide, the share of the population who was black fluctuated between 10 and 13 percent in the years shown here, however the share of lynching victims who were black was almost 73 percent. North-south divide Of the 4.7 thousand victims of lynching between 1882 and 1968, over 3.5 thousand of these were killed in former-Confederate states. Of the fourteen states where the highest number of lynching victims were killed, eleven were former-Confederate states, and all saw the deaths of at least one hundred people due to lynching. Mississippi was the state where most people were lynched in these years, with an estimated 581 victims, 93 percent of whom were black. Georgia saw the second most lynchings, with 531 in total, and the share of black victims was also 93 percent. Compared to the nationwide average of 73 percent, the share of black victims in former-Confederate states was 86 percent. Texas was the only former-Confederate state where this share (71 percent) was below the national average, due to the large number of Mexicans who were lynched there. Outside of the south Of the non-Confederate state with the highest number of lynching victims, most either bordered the former-Confederate states, or were to the west. Generally speaking, the share of white victims in these states was often higher than in the south, meaning that the majority took place in the earlier years represented here; something often attributed to the lack of an established judiciary system in rural regions, and the demand for a speedy resolution. However, there are many reports of black people being lynched in the former border states in the early-20th century, as they made their way northward during the Great Migration. Between 1882 and 1968, lynchings were rare in the Northeast, although Connecticut, Massachusetts, New Hampshire and Rhode Island were the only states** without any recorded lynchings in these years.

Throughout the 17th century, St Domingue (Haiti) was the largest producer of sugar in the world (unfortunately no annual data is available in this source); with the Haitian revolution in 1791, however, Haiti became the first independent state in the Caribbean, and its share of the international sugar market all-but disappeared. By the mid-1800s, European investment in Cuba led to it becoming the world leader in the sugar industry; a position it would hold until the 1960s, when it was overtaken by Brazil.

Slavery and the "sugar bowl of the world" The brief annexation of Cuba by the British in the 1760s saw an influx of investment from European merchants into Cuba's undermanned sugar plantations, who aimed to exploit Cuba's abundant resources and rival the dominance of St Domingue. With this investment and opening of international trade, plantation owners in Cuba began importing slave labor to meet the overwhelming demand; as a result, Cuba became one of the most common destinations for African slaves in the 19th century. Slavery was eventually abolished in Cuba in 1886, however this did little to disrupt Cuba's sugar output, and migrant workers were imported form Asia (namely, China) to meet labor demands.

From the data, the first major disruption to Cuba's sugar output came in the 1890s, during the Cuban War of Independence (1895-1898), when it dropped by over 77.5 percent between 1894 and 1895. Production increased significantly in the early 20th century, due to agricultural mechanization, and output was between four and five million metric tons in the late 1920s; however, the Great Depression then saw Cuba's sugar output drop from 5.2 million tons in 1928 to just 1.9 million tons by 1932. Annual output then grew significantly following the Second World War, exceeding five (sometimes even eight) million tons per year; nonetheless, output fluctuated greatly, with observable changes during milestone years in Cuban history, such as the military coup in the early 1950s, the Cuban Missile Crisis and U.S. trade embargo in 1962, and Castro's (failed) attempt to harvest ten million tons of sugar in 1970 to boost the Cuban economy.