In the early 1850s Brazil's population numbered a little over seven and a half million. It was concentrated, as it always had been, along the eastern seaboard. Forty per cent lived in three south-eastern provinces – Rio de Janeiro, Minas Gerais and São Paulo – and the capital city of Rio de Janeiro with its 180,000 residents. The north-east, the principal area of settlement in colonial times, still accounted for 44 per cent. Black and mulatto slaves probably numbered between two and two and a half million, that is, between a quarter and a third of the population. By 1872, at the time of the first national census, Brazil's total population had increased to ten million. The proportion in the north-east had declined to 40 per cent while the city of Rio had grown to 275,000. Twenty years after the end of the slave trade the number of slaves had fallen to one and a half million (15 per cent), and a larger proportion of the slave population was to be found in the provinces of Rio de Janeiro, São Paulo and Minas Gerais. The rapid growth of coffee exports in the south-east, along with a relative decline of sugar, explains the regional shift in population from 1850 to 1870. Rio de Janeiro's commercial class prospered as the coffee trade linked planters to the international economy. Labour, however, whether slave or free, rural or urban, received little of the increased wealth.