Demography is the science of populations, which seek to understand population dynamics by investigating three main demographic processes: birth, migration, and aging (including death). Based on the demographic research of the earth, earth’s population up to the year 2050 and 2100 can be estimated by demographers. Demographics are quantifiable characteristics of a given population. Demographic indicators could include population size, population growth rate, crude birth rate, crude death rate, total fertility rate, life expectancy and infant mortality. Demography is today widely taught in many universities across the world, attracting students with initial training in social sciences, statistics or health studies.