Population âgée de plus de 18 ans parlant allemand, français où italien

Random sampling in three stages in 2008: •Sample of postal codes drawn from each of the large regions of Switzerland •Selection of a determinate number of households/addresses from each of the sampled postal codes •Designation of one person from each household/address

Nombre d'adresses libérées: 2970 Interviews valides: 1271 Repeated cross sectional (1981, 1990, 1999, 2008) in Switzerland: 1990 and 2008 M.I.S. Trend