John Graunt, was born on April 24, 1620 in London. He died on April 18, 1674, also in London. He is an English Statistician, considered to be the founder of Science of Demography in the statistical study of human population. His analysis of important statistics on London residents influenced pioneer demographic work of his friend Sir William Petty who is also a royal astronomer.
He was an entrepreneur who advanced until his business was destroyed in a fire in London in 1666. Graunt began operating a municipal office and a militia command. Although he was still active as a businessman, he began to study the death records kept by church members in London since 1532. Looking at the phenomenon of statistical deaths that often occurred, his idea of “Natural and Political Observation” was based on the Bill of Mortality 1662. He produced four editions of this work; the third (1665) was published by the Royal Society, where Graunt was a charter member.
Graunt classifies death rates according to the causes of death, including the numerous number of people. He noted that mortality rates in urban areas exceeded in rural areas. He also found that although male birth rates were higher than women, they were offset by higher mortality rates for men, so the population was almost equal between sexes. The most important innovation is the study of the life table, which illustrates the mortality rate in terms of survival using only two survival rates (ages 6 and 76), obtained from actual observation. He predicts the percentage of people who will survive for consecutive years and their lifespan year after year. Petty also predicted that the estimated social economic losses caused by death.