Nine of every 10 people added to the world's population over the
next 15 years will be in developing economies
Commentary
About the data
Definitions
Data sources
Population growth rates have started to decline in many countries, but the absolute numbers continue to increase, and more people will be added to the world's population in the 1990s than in any previous decade. The world's population was estimated to be 5.7 billion in mid-1995and growing by 230,000 people a day.
Sub-Saharan Africa is projected to grow at 2.6 percent a year, Europe at a barely noticeable 0.1 percent a year. Such regional disparities will gradually change the relative distribution of people, with fast-growing continents dramatically increasing their share of the global population.
In low-income economies more than a third of the population is under age 15, compared with less than a fifth in high-income economies. In high-income economies there are roughly two people of working age to support each person who is either too young or too old to work. In low-income economies this ratio is around 1.5 to 1 because of the large population under 15. But the transition to lower population growth also poses social and economic problems. As growth slows, the average age of the population rises, and the proportion of elderly people eventually increases. Many low-growth economies already face crises in their pension and social security systems.
Population estimates are based on national censuses. Precensus and postcensus estimates are interpolations or projections. The international comparability of population indicators is limited by differences in the concepts, definitions, data collection procedures, and estimation methods used by national statistical agencies and other organizations that collect the data. In addition, the frequency and quality of coverage of population censuses vary by country and region.
Of the 148 economies here, 117 conducted a census between 1987 and 1995. The proportion is 80 percent for high-income countries and 86 percent for low- and middle-income countries. The recentness of a census, along with the availability of complementary data from surveys or registration systems, is one of the many objective means for judging the quality of demographic data (see Primary data documentation for the most recent census or survey year and for registration completion status).
For developing countries that lack recent census-based population data, population figures are estimates provided by national statistical offices or the United Nations Population Division. Population projections require fertility, mortality, and net migration estimates based on demographic data collected from sample surveys, some of which may be small in size or have limited coverage. These estimates are the product of demographic modeling and are susceptible to biases and errors due to shortcomings of the model and the data.
The governmental and political climate also affects the quality of official demographic data. The trust and cooperation of the public, the government's commitment to full and accurate enumeration, the confidentiality and protection against misuse accorded to census data, and the independence of census agencies from unreasonable political influence all affect the quality and reliability of the data.
The population projections here are based on World Bank staff estimates using the cohort component method. Mortality, fertility, and net migration are projected separately by age-sex group and applied to the 1990 base year age-sex structure. For countries in which fertility has begun to decline to replacement level (countries making the "fertility transition"), this trend is assumed to continue. For countries in which this event has not yet occurred, the current fertility rate is assumed to decline at the average rate of countries making the fertility transition. Countries with below-replacement fertility are assumed to have constant fertility rates in 1995-2000 and to regain replacement fertility by 2030.
Definitions
Total population is based on the de facto definition of population, which counts all residents regardless of legal status or citizenship. Refugees not permanently settled in the country of asylum are generally considered to be part of the population of their country of origin. The indicators shown are midyear estimates for 1980 and 1995 and projections for 2010.
Average annual growth rate is calculated as the exponential change for the period indicated. See Statistical methods for more information.
Age dependency ratio is calculated as the ratio of dependents-the population under age 15 and above age 65-to the working-age population-those aged 15-64.
Population aged 60 and above represents the proportion of the population that is aged 60 and above.
Women per 100 men aged 60 and above is the ratio of women to men in that age group.
Population estimates are produced by the World Bank's Human Development and International Economics Departments in consultation with World Bank country departments. Important inputs to the World Bank's demographic work come from the following sources:
Population censuses. United Nations Department of Economic and Social Information and Policy Analysis, World Population Prospects: The 1996 Edition and Population and Vital Statistics Report. Eurostat, Demographic Statistics. Council of Europe, Recent Demographic Developments in Europe and North America (1995). Bureau of the Census, World Population Profile 1996. Projections are based on the method discussed in Bos and others, World Population Projections 1994-95.