The Demography of the World Population from 1950 to 2100. Data source: United Nations — World Population Prospects 2017 Demography (from Ancient Greek δῆμος (dêmos) 'people, society' and -γραφία (-graphía) 'writing, drawing, description')[1] is the statistical study of human populations: their size, composition (e.g., ethnic group, age), and how they change through the interplay of fertility (birt