According to the Irish census of 1841, the population of Ireland
exceeded 8 million. By 1851, the population, which should have been about 9 million, had dropped to 6 million. Thus, close to 3 million people were lost to The Great Hunger: more than 1 million to death by starvation and related diseases, and more than 2 million to emigration, which continued at high rates through 1921. By then, 4.5 million people had left Ireland.
During the period 1845-50, Britain’s total expenditure in Ireland was £7 million, or 0.01 percent of its gross national product during the period. Irish expenditures from local taxes and landlord borrowing totaled £8.5 million. In the previous decade, the British government had given slaveholders in the West Indies £20 million as compensation for ending slavery.