PNAD, the Brazilian National Household Sample Survey, is a survey conducted annually by IBGE since 1981. PNAD investigates several characteristics of the population such as household composition, education, labor, income and fertility. Moreover, almost every year, there is an investigation of an additional topic, such as education, health, professional training and food security. PNAD's sample in 2012 consisted of 147,203 households, with 362,451 individuals.