Traditionally in Korea, the typical family size is quite large, with three or four generations usually living together under the same roof. Because infant mortality was high and a big family was thought of as a blessing, having many children was the desired option. However, as the country underwent rapid industrialization and urbanization during the 1960s and 1970s the pattern was accompanied by an effective birth control drive, and the average number of children in a family dramatically decreased to two or less in the 1980s.