Obtaining reliable gender statistics that adequately reflect differences and inequalities in the situation of women and men in all areas of life requires a strategy of gender mainstreaming in all stages of data production. This means that gender is brought into the “mainstream” of all statistical activities, rather than dealt with as an “add-on” (United Nations, 2002). Mainstreaming a gender perspective in statistics means that gender issues and gender-based biases are systematically taken into account in the production of all official statistics and at all stages of data production (Hedman, Perucci and Sundstrom, 1996; United Nations-, 2001a, 2001b, 2002, 2006).