Exclusion has many faces. Despite real progress since 2000 towards universal primary education, 72 million children are still not enrolled at all in school. More than half are girls. Seven out of ten live in sub-Saharan Africa or South and West Asia. Poverty and marginalization are major causes of exclusion. Households in rural or remote communities and children in urban slums have less access to education. Disabled children suffer from blatant educational exclusion – they account for one third of all out-of-school children. Working children, those belonging to indigenous groups and linguistic minorities, nomadic children and those affected by HIV/AIDS are among the vulnerable groups. Some 37 per cent of out-of-school children live in 35 states defined as fragile by the Organisation for Economic Co-operation and Development, but these do not include all places facing conflict and post-conflict situations. In every case children are at enormous risk of missing out on an education.