Through 1990, the population from which the sample was drawn consisted of all eligible West German and West Berlin voters living in private households. Owing to reunification, an additional survey was conducted in 1991 outside the normal two-year cycle, and since then the population has been widened to include the resident adult population (e.g., both Germans and foreigners) of both western and eastern states. From 1980 to 1990 the sample consisted of 3,000 West German and West Berlin respondents. In 1991, 1,500 respondents were selected from the western and 1,500 from the eastern states. Since 1992, the sample has been weighted by population such that 2,400 interviews are conducted in the western states and 1,100 in the eastern states. Samples from 1980 to 1992, as well as in 1998, were drawn following the ADM sample design. By contrast, in 1994 and 1996 samples were drawn from the lists of addresses kept by the community offices in Germany which register residents.