Demography is the study of human populations in terms of various factors such as size, location, age, gender, occupation, etc. It is important because understanding demographic factors and trends can provide insight into markets. Some key demographic trends include the declining ratio of children to older citizens globally, a shift from communicable to non-communicable diseases, and rapidly aging populations in some countries. The ratio of workers to older dependents is rising in many countries. Exploiting the demographic dividend of a rising working age population is also becoming more difficult.