Demography
Demography (from Ancient Greek δῆμος (dêmos) 'people, society' and -γραφία (-graphía) 'writing, drawing, description') is the statistical study of human populations: their size, composition (e.g., ethnic group, age), and how they change through the interplay of fertility (births), mortality (deaths), and migration. Formal demography limits its object of study to the measurement of population processes, while the broader field of social demography (or population studies) also analyses the relationships among economic, social, institutional, cultural, and biological processes that influence a population.