The feeling that the early 20th century was an era of economic growth due to technological advances contrasted dramatically with the standard of living of lower social classes. The growth of the previous decades led to an unprecedented population explosion starting in 1929. The Great Depression caused the collapse of the nitrate industry in the north, leaving 60,000 unemployed, which added to the decline in agricultural exports, resulting in a total number for the unemployed to be about 300,000 nationwide. These unemployed workers saw Santiago and its booming industry as the only chance to survive. Many migrants arrived in Santiago with nothing and thousands had to survive on the streets due to the great difficulty in finding a place they could rent. Widespread disease, including tuberculosis, claimed the lives of hundreds of the homeless. Unemployment and living costs increased dramatically whilst the salaries of the population of Santiago fell.