Consumer Price Indices (CPIs) are economic indicators constructed to measure the changes over time in the prices of consumer goods and services acquired, used or paid for by households. Harmonized Indices of Consumer Prices (HICPs) are designed for international comparisons of consumer price inflation. They are used in the assessment of inflation convergence as required under Article 121 of the Treaty of Amsterdam (Article 109j of the Treaty on European Union). The coverage of the HICPs is defined in terms of household final monetary consumption expenditure , by reference to the national accounts concepts of the European System of Accounts (ESA 1995). Expenditures are classified according to the COICOP/HICP (Classification of Individual Consumption by Purpose adapted to the needs of HICPs).