The infant mortality rate is the annual number of deaths of children under one year of age per 1 000 live births. Some international variation in infant mortality rates may be due to country variation in defining live children following birth. Most countries have no gestational age or weight limits for mortality registration. Minimal limits exist for Norway (to be counted as a death following a live birth, the gestational age must exceed 12 weeks) and in the Czech Republic, France, the Netherlands and Poland a minimum gestational age of 22 weeks and/or a weight threshold of 500 g is applied (EURO-PERISTAT Project 2008, Table 3.1, p. 40). Household income and income inequality data are discussed in GE1 and EQ1. The Gini coefficient is a measure of income inequality. Values range between 0 – perfect equality – and 1 – all income goes to one person.