The IPCA is a consumer price index produced by Instituto Brasileiro de Geografia e Estatistica (IBGE), in Rio de Janeiro. The index is used by Brazil's government to set benchmark interest rates and make monetary policy decisions. The index measures the percentage change in consumer prices for a 30-day period, beginning the first day of each month and uses the previous month as its reference. The base period is December 1993=100. IPCA reflects consumption by families whose incomes range from the national minimum wage to 40 times minimum wage (for minimum wage see, BZMW Index <Go>). The index is for urban areas, including Rio de Janeiro, Porto Alegre, Belo Horizonte, Recife, Sao Paulo, Belem, Fortaleza, Salvador, the federal district of Brasilia, Curitiba and Goiania. IPCA is composed of following categories: food (22.74%), housing (13.3%), household items (4.17%), clothing (6.76%), transportation (18.94%), healthcare (10.89%), personal items (10.38%), education (7.23%) and communication (5.57%). For this index, IBGE considers only M1 purchases and weights the sample basket according to region and income.