About the data
Definitions
Data sources

About the data

Population, land area, and output are important measurements of economy size. They also provide a broad indication of actual and potential resources. Therefore, population, land area, and output—as measured by gross national product (GNP) or gross domestic product (GDP)—are used throughout the World Development Indicators to normalize other indicators.

Population estimates are generally based on extrapolations from the most recent national census. See About the data for tables 2.1 and 2.2 for further discussion on the measurement of population and population growth.

Land area is particularly important for understanding the agricultural capacity of an economy and the effects of human activity on the environment. See tables 3.1-3.4 for other measures of land area, rural population density, land use, and productivity. Land area differs from other measures of geographic size such as surface area, which includes inland bodies of water and some coastal waterways, and gross area which may include offshore territorial waters. Recent innovations in satellite mapping techniques and computer databases have resulted in more precise measurements of land and water areas.

GNP, the broadest measure of national income, measures the total domestic and foreign value added claimed by residents. GNP comprises GDP plus net receipts of primary income from nonresident sources. The World Bank uses GNP per capita in U.S. dollars to classify countries for analytical purposes and to determine borrowing eligibility. See the Users guide for definitions of the income groups used in this book. Also see About the data for tables 4.1 and 4.2 for further discussion of the usefulness of national income as a measure of productivity or welfare.

When calculating GNP in U.S. dollars from GNP reported in national currencies, the World Bank follows its Atlas conversion method. This involves using a three-year average of exchange rates to smooth the effects of transitory exchange rate fluctuations. See Statistical methods for further discussion of the Atlas method. Note that growth rates are calculated from data in constant prices and national currency units, not from the Atlas estimates.

Because exchange rates do not always reflect international differences in relative prices, this table also shows GNP and GNP per capita estimates that are converted into international dollars using purchasing power parities (PPPs). PPPs provide a standard measure of real price levels between countries, just as conventional price indexes calculate real values over time. The PPP conversion factors used here are derived from the most recent round of price surveys—covering 118 countries—conducted by the International Comparison Programme (ICP). The surveys, completed in 1996, are based on a 1993 reference year. Estimates for countries not included in the survey are derived from statistical models using available data. See About the data for tables 4.10 and 4.11 for more information on the ICP and the calculation of PPPs.

Definitions

• Population is based on the de facto definition of population, which counts all residents regardless of legal status or citizenship—except for refugees not permanently settled in the country of asylum, who are generally considered part of the population of the country of origin. The values shown are midyear estimates for 1996. See also table 2.1. • Land area is a country’s total area, excluding areas under inland bodies of water. • Population density is midyear population divided by land area in square kilometers. • Gross national product (GNP) is the sum of value added by all resident producers plus any taxes (less subsidies) that are not included in the valuation of output plus net receipts of primary income (employee compensation and property income) from nonresident sources. Data are in current U.S. dollars converted using the World Bank Atlas method (see Statistical methods). Growth is calculated from constant price GNP in national currency units. • GNP per capita is gross national product divided by midyear population. GNP per capita in U.S. dollars is converted using the World Bank Atlas method. Growth is calculated from constant price GNP per capita in national currency units. • GNP PPP is gross national product converted to international dollars using purchasing power parity rates. An international dollar has the same purchasing power over GNP as the U.S. dollar in the United States. All ranks are calculated for economies reporting data.

Data sources

Population estimates are prepared by World Bank staff from a variety of sources (see Data sources for table 2.1). Data on land area are from the Food and Agriculture Organization (see Data sources for table 3.1). GNP per capita is estimated by World Bank staff based on national accounts data collected by World Bank staff during economic missions or reported by national statistical offices to other international organizations such as the OECD. Data for high-income OECD economies come from the OECD. Purchasing power parity conversion factors are estimates by World Bank staff based on data collected by the International Comparison Programme.

THE WORLD BANK METHODOLOGY:

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Size of the economy

Quality of life

Development progress

Trends in long-term development

Long-term structural change

Key indicators for other economies

Population

Land use and deforestation

Growth of output

Credit, investment and expenditures

Integration with the global economy

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