Population is determined by three main factors: natality, mortality, and migration.

Lower Mortality Rate:

All over the world, improved access to health care, information, and communication has resulted in people living longer. For example, the life expectancy in the USA was 68 years in 1950. Today in 2021, the life expectancy in the US has increased to over 76 years.

Higher Natality:

Advancements in healthcare, pharmaceuticals, and information have combined to reduce the number of babies who die before, during, and after birth. Access to immunization and improved child care have also helped to increase the chances of children surviving. For example, Approximately 1300 infants in the USA died in 1980 (1.3%) per 100,000. In 2014 the rate was reduced by half to approximately 600 infant deaths per 100,000 (0.6%)

Increased Migration:

Personal, economic, environmental, and social factors may force people to migrate to other places. In the past decade, international migration has been on the rise, particularly for economic reasons. One report indicates that about 10% of the population of developed countries is comprised of international migrants, who commonly migrate for economic reasons. By 2050, between 15 and 36 percent of the population of various countries in Western Europe is projected to be of “foreign origin.”