Between 1815 and 1865 the population of the German Confederation (excluding Austria) grew around 60% from 21 million to 34 million. Simultaneously the Demographic Transition took place as the high birth rates and high death rates of the pre-industrial country shifted to low birth and death rates of the fast-growing industrialized urban economic and agricultural system. Increased agricultural productivity secured a steady food supply, as famines and epidemics declined. This allowed people to marry earlier, and have more children. The high birthrate was offset by a very high rate of infant mortality and after 1840, large-scale emigration to the United States. Emigration totaled at 480,000 in the 1840s, 1,200,000 in the 1850s, and at 780,000 in the 1860s. The upper and middle classes first practiced birth control, soon to be universally adopted.