In 1800, the population of Ethiopia was 2.95 million. Like most other Sub-Saharan countries, Ethiopia experienced slow but steady growth for much of the 18th century, and growth which would increase exponentially as the country entered the 20th century. Ethiopia’s population grew more rapidly as the 20th century progressed, however, this growth was offset in the late 1970s, with the beginning of the Ethiopian Civil War and the coinciding Qey Shibir (Red Terror) campaign. However, despite experiencing a significant famine from 1983 to 1985, which would result in approximately one million deaths, Ethiopia’s population would begin to grow rapidly once more, from 35 million in 1980 to 66 million by the beginning of the 21st century. By 2020, Ethiopia is estimated to have a population of almost 115 million, with some experts predicting that Ethiopia may become one of the most populous countries in the world by 2100.
Attribution 4.0 (CC BY 4.0)https://creativecommons.org/licenses/by/4.0/
License information was derived automatically
Rural population (% of total population) in Ethiopia was reported at 76.34 % in 2024, according to the World Bank collection of development indicators, compiled from officially recognized sources. Ethiopia - Rural population - actual values, historical data, forecasts and projections were sourced from the World Bank on July of 2025.
IPUMS-International is an effort to inventory, preserve, harmonize, and disseminate census microdata from around the world. The project has collected the world's largest archive of publicly available census samples. The data are coded and documented consistently across countries and over time to facillitate comparative research. IPUMS-International makes these data available to qualified researchers free of charge through a web dissemination system.
The IPUMS project is a collaboration of the Minnesota Population Center, National Statistical Offices, and international data archives. Major funding is provided by the U.S. National Science Foundation and the Demographic and Behavioral Sciences Branch of the National Institute of Child Health and Human Development. Additional support is provided by the University of Minnesota Office of the Vice President for Research, the Minnesota Population Center, and Sun Microsystems.
National coverage
Household
All housing units and households; all individuals who passed the night of the census date in the dwelling
Census/enumeration data [cen]
MICRODATA SOURCE: Central Statistical Agency
SAMPLE DESIGN: Systematic sample of every 10th household with a random start, drawn by the country. NOTE: The sample includes data from both the short and the long questionnaire. Only one-fifth of household received the long questionnaire, thus only 20% of the population have responses for most variables.
SAMPLE UNIT: household
SAMPLE FRACTION: 10%
SAMPLE SIZE (person records): 7,434,086
Face-to-face [f2f]
Two census questionnaires, a short form and a long form, collected information in five sections: 1) Area identification, 2) Type of residence and housing identification, 3) Details of persons in the household, 4) Deaths in the household during the last 12 month, and 5) Information on housing unit. The long questionnaire was administerd to 1 in 5 households in each enumeration area. The short questionnaire with a subset of the long questionnaire items corresponding to basic demographic and social characteristics (population size, sex, age, religion, mother tongue, ethnic group, disability and orphanage) was administered to the remaining (non-sample) households.
This statistic shows the total population of Ethiopia from 2013 to 2023 by gender. In 2023, Ethiopia's female population amounted to approximately 64.21 million, while the male population amounted to approximately 64.49 million inhabitants.
Attribution 4.0 (CC BY 4.0)https://creativecommons.org/licenses/by/4.0/
License information was derived automatically
Population, female (% of total population) in Ethiopia was reported at 49.9 % in 2024, according to the World Bank collection of development indicators, compiled from officially recognized sources. Ethiopia - Population, female (% of total) - actual values, historical data, forecasts and projections were sourced from the World Bank on July of 2025.
The 2005 Ethiopia Demographic and Health Survey (2005 EDHS) is part of the worldwide MEASURE DHS project which is funded by the United States Agency for International Development (USAID).
The principal objective of the 2005 Ethiopia Demographic and Health Survey (DHS) is to provide current and reliable data on fertility and family planning behaviour, child mortality, adult and maternal mortality, children’s nutritional status, the utilization of maternal and child health services, knowledge of HIV/AIDS and prevalence of HIV/AIDS and anaemia.
The specific objectives are to: - collect data at the national level which will allow the calculation of key demographic rates; - analyze the direct and indirect factors which determine the level and trends of fertility; - measure the level of contraceptive knowledge and practice of women and men by method, urban-rural residence, and region; - collect high quality data on family health including immunization coverage among children, prevalence and treatment of diarrhoea and other diseases among children under five, and maternity care indicators including antenatal visits and assistance at delivery; - collect data on infant and child mortality and maternal and adult mortality; - obtain data on child feeding practices including breastfeeding and collect anthropometric measures to use in assessing the nutritional status of women and children; - collect data on knowledge and attitudes of women and men about sexually transmitted diseases and HIV/AIDS and evaluate patterns of recent behaviour regarding condom use; - conduct haemoglobin testing on women age 15-49 and children under age five years in a subsample of the households selected for the survey to provide information on the prevalence of anaemia among women in the reproductive ages and young children; - collect samples for anonymous HIV testing from women and men in the reproductive ages to provide information on the prevalence of HIV among the adult population.
This information is essential for informed policy decisions, planning, monitoring, and evaluation of programs on health in general and reproductive health in particular at both the national and regional levels. A long-term objective of the survey is to strengthen the technical capacity of the Central Statistical Agency to plan, conduct, process, and analyse data from complex national population and health surveys. Moreover, the 2005 Ethiopia DHS provides national and regional estimates on population and health that are comparable to data collected in similar surveys in other developing countries. The first ever Demographic and Health Survey (DHS) in Ethiopia was conducted in the year 2000 as part of the worldwide DHS programme. Data from the 2005 Ethiopia DHS survey, the second such survey, add to the vast and growing international database on demographic and health variables.
Wherever possible, the 2005 EDHS data is compared with data from the 2000 EDHS. In addition, where applicable, the 2005 EDHS is compared with the 1990 NFFS, which also sampled women age 15-49. Husbands of currently married women were also covered in this survey. However, for security and other reasons, the NFFS excluded from its coverage Eritrea, Tigray, Asseb, and Ogaden autonomous regions. In addition, fieldwork could not be carried out for Northern Gondar, Southern Gondar, Northern Wello, and Southern Wello due to security reasons. Thus, any comparison between the EDHS and the NFFS has to be interpreted with caution.
National
Sample survey data
The 2005 EDHS sample was designed to provide estimates for the health and demographic variables of interest for the following domains: Ethiopia as a whole; urban and rural areas of Ethiopia (each as a separate domain); and 11 geographic areas (9 regions and 2 city administrations), namely: Tigray; Affar; Amhara; Oromiya; Somali; Benishangul-Gumuz; Southern Nations, Nationalities and Peoples (SNNP); Gambela; Harari; Addis Ababa and Dire Dawa. In general, a DHS sample is stratified, clustered and selected in two stages. In the 2005 EDHS a representative sample of approximately 14,500 households from 540 clusters was selected. The sample was selected in two stages. In the first stage, 540 clusters (145 urban and 395 rural) were selected from the list of enumeration areas (EA) from the 1994 Population and Housing Census sample frame.
In the census frame, each of the 11 administrative areas is subdivided into zones and each zone into weredas. In addition to these administrative units, each wereda was subdivided into convenient areas called census EAs. Each EA was either totally urban or rural and the EAs were grouped by administrative wereda. Demarcated cartographic maps as well as census household and population data were also available for each census EA. The 1994 Census provided an adequate frame for drawing the sample for the 2005 EDHS. As in the 2000 EDHS, the 2005 EDHS sampled three of seven zones in the Somali Region (namely, Jijiga, Shinile and Liben). In the Affar Region the incomplete frame used in 2000 was improved adding a list of villages not previously included, to improve the region's representativeness in the survey. However, despite efforts to cover the settled population, there may be some bias in the representativeness of the regional estimates for both the Somali and Affar regions, primarily because the census frame excluded some areas in these regions that had a predominantly nomadic population.
The 540 EAs selected for the EDHS are not distributed by region proportionally to the census population. Thus, the sample for the 2005 EDHS must be weighted to produce national estimates. As part of the second stage, a complete household listing was carried out in each selected cluster. The listing operation lasted for three months from November 2004 to January 2005. Between 24 and 32 households from each cluster were then systematically selected for participation in the survey.
Because of the way the sample was designed, the number of cases in some regions appear small since they are weighted to make the regional distribution nationally representative. Throughout this report, numbers in the tables reflect weighted numbers. To ensure statistical reliability, percentages based on 25 to 49 unweighted cases are shown in parentheses and percentages based on fewer than 25 unweighted cases are suppressed.
Note: See detailed sample implementation table in APPENDIX A of the survey report.
Face-to-face [f2f]
In order to adapt the standard DHS core questionnaires to the specific socio-cultural settings and needs in Ethiopia, its contents were revised through a technical committee composed of senior and experienced demographers of PHCCO. After the draft questionnaires were prepared in English, copies of the household, women’s and men’s questionnaires were distributed to relevant institutions and individual researchers for comments. A one-day workshop was organized on November 22, 2004 at the Ghion Hotel in Addis Ababa to discuss the contents of the questionnaire. Over 50 participants attended the national workshop and their comments and suggestions collected. Based on these comments, further revisions were made on the contents of the questionnaires. Some additional questions were included at the request of MOH, the Fistula Hospital, and USAID. The questionnaires were finalized in English and translated into the three main local languages: Amharic, Oromiffa and Tigrigna. In addition, the DHS core interviewer’s manual for the Women’s and Men’s Questionnaires, the supervisor’s and editor’s manual, and the HIV and anaemia field manual were modified and translated into Amharic.
The Household Questionnaire was used to list all the usual members and visitors in the selected households. Some basic information was collected on the characteristics of each person listed, including age, sex, education, and relationship to the head of the household. The main purpose of the Household Questionnaire was to identify women and men who were eligible for the individual interview. The Household Questionnaire also collected information on characteristics of the household’s dwelling unit, such as the source of water, type of toilet facilities, materials used for the floor and roof of the house, ownership of various durable goods, and ownership and use of mosquito nets. In addition, this questionnaire was used to record height and weight measurements of women age 15-49 and children under the age of five, households eligible for collection of blood samples, and the respondents’ consent to voluntarily give blood samples.
The Women’s Questionnaire was used to collect information from all women age 15-49 years and covered the following topics. - Household and respondent characteristics - Fertility levels and preferences - Knowledge and use of family planning - Childhood mortality - Maternity care - Childhood illness, treatment, and preventative actions - Anaemia levels among women and children - Breastfeeding practices - Nutritional status of women and young children - Malaria prevention and treatment - Marriage and sexual activity - Awareness and behaviour regarding AIDS and STIs - Harmful traditional practices - Maternal mortality
The Men’s Questionnaire was administered to all men age 15-59 years living in every second household in the sample. The Men’s Questionnaire collected similar information contained in the Women’s Questionnaire, but was shorter because it did not contain questions on reproductive
Attribution 4.0 (CC BY 4.0)https://creativecommons.org/licenses/by/4.0/
License information was derived automatically
Population ages 65 and above (% of total population) in Ethiopia was reported at 3.23 % in 2024, according to the World Bank collection of development indicators, compiled from officially recognized sources. Ethiopia - Population ages 65 and above (% of total) - actual values, historical data, forecasts and projections were sourced from the World Bank on July of 2025.
Attribution 4.0 (CC BY 4.0)https://creativecommons.org/licenses/by/4.0/
License information was derived automatically
Ethiopia: Percent urban population: The latest value from 2023 is 23.16 percent, an increase from 22.66 percent in 2022. In comparison, the world average is 61.36 percent, based on data from 196 countries. Historically, the average for Ethiopia from 1960 to 2023 is 13.4 percent. The minimum value, 6.43 percent, was reached in 1960 while the maximum of 23.16 percent was recorded in 2023.
In 2023, the annual population growth in Ethiopia remained nearly unchanged at around 2.6 percent. Yet 2023 saw the lowest population growth in Ethiopia with 2.6 percent. Population growth deals with the annual change in total population, and is affected by factors such as fertility, mortality, and migration.Find more key insights for the annual population growth in countries like Uganda and Somalia.
Attribution 4.0 (CC BY 4.0)https://creativecommons.org/licenses/by/4.0/
License information was derived automatically
<ul style='margin-top:20px;'>
<li>Ethiopia population growth rate for 2022 was <strong>2.62%</strong>, a <strong>0.05% decline</strong> from 2021.</li>
<li>Ethiopia population growth rate for 2021 was <strong>2.67%</strong>, a <strong>0.04% decline</strong> from 2020.</li>
<li>Ethiopia population growth rate for 2020 was <strong>2.71%</strong>, a <strong>0.02% increase</strong> from 2019.</li>
</ul>Annual population growth rate for year t is the exponential rate of growth of midyear population from year t-1 to t, expressed as a percentage . Population is based on the de facto definition of population, which counts all residents regardless of legal status or citizenship.
The 2016 Ethiopia Demographic and Health Survey (EDHS) is the fourth Demographic and Health Survey conducted in Ethiopia. It was implemented by the Central Statistical Agency (CSA) at the request of the Federal Ministry of Health (FMoH). Data collection took place from January 18, 2016, to June 27, 2016.
SURVEY OBJECTIVES The primary objective of the 2016 EDHS is to provide up-to-date estimates of key demographic and health indicators. The EDHS provides a comprehensive overview of population, maternal, and child health issues in Ethiopia. More specifically, the 2016 EDHS: - Collected data at the national level that allowed calculation of key demographic indicators, particularly fertility and under-5 and adult mortality rates - Explored the direct and indirect factors that determine levels and trends of fertility and child mortality - Measured levels of contraceptive knowledge and practice - Collected data on key aspects of family health, including immunisation coverage among children, prevalence and treatment of diarrhoea and other diseases among children under age 5, and maternity care indicators such as antenatal visits and assistance at delivery - Obtained data on child feeding practices, including breastfeeding - Collected anthropometric measures to assess the nutritional status of children under age 5, women age 15-49, and men age 15-59 - Conducted haemoglobin testing on eligible children age 6-59 months, women age 15-49, and men age 15-59 to provide information on the prevalence of anaemia in these groups - Collected data on knowledge and attitudes of women and men about sexually transmitted diseases and HIV/AIDS and evaluated potential exposure to the risk of HIV infection by exploring high-risk behaviours and condom use - Conducted HIV testing of dried blood spot (DBS) samples collected from women age 15-49 and men age 15-59 to provide information on the prevalence of HIV among adults of reproductive age - Collected data on the prevalence of injuries and accidents among all household members - Collected data on knowledge and prevalence of fistula and female genital mutilation or cutting (FGM/C) among women age 15-49 and their daughters age 0-14 - Obtained data on women’s experience of emotional, physical, and sexual violence.
As the fourth DHS conducted in Ethiopia, following the 2000, 2005, and 2011 EDHS surveys, the 2016 EDHS provides valuable information on trends in key demographic and health indicators over time. The information collected through the 2016 EDHS is intended to assist policymakers and programme managers in evaluating and designing programmes and strategies for improving the health of the country’s population.
Additionally, the 2016 EDHS included a health facility component that recorded data on children’s vaccinations, which were then combined with the household data on vaccinations.
National coverage
Household members women age 15-49 men age 15-59 children under age 5
Sample survey data [ssd]
The sampling frame used for the 2016 EDHS is the Ethiopia Population and Housing Census (PHC), which was conducted in 2007 by the Ethiopia Central Statistical Agency. The census frame is a complete list of 84,915 enumeration areas (EAs) created for the 2007 PHC. An EA is a geographic area covering on average 181 households. The sampling frame contains information about the EA location, type of residence (urban or rural), and estimated number of residential households. With the exception of EAs in six zones of the Somali region, each EA has accompanying cartographic materials. These materials delineate geographic locations, boundaries, main access, and landmarks in or outside the EA that help identify the EA. In Somali, a cartographic frame was used in three zones where sketch maps delineating the EA geographic boundaries were available for each EA; in the remaining six zones, satellite image maps were used to provide a map for each EA.
Administratively, Ethiopia is divided into nine geographical regions and two administrative cities. The sample for the 2016 EDHS was designed to provide estimates of key indicators for the country as a whole, for urban and rural areas separately, and for each of the nine regions and the two administrative cities.
The 2016 EDHS sample was stratified and selected in two stages. Each region was stratified into urban and rural areas, yielding 21 sampling strata. Samples of EAs were selected independently in each stratum in two stages. Implicit stratification and proportional allocation were achieved at each of the lower administrative levels by sorting the sampling frame within each sampling stratum before sample selection, according to administrative units in different levels, and by using a probability proportional to size selection at the first stage of sampling.
In the first stage, a total of 645 EAs (202 in urban areas and 443 in rural areas) were selected with probability proportional to EA size (based on the 2007 PHC) and with independent selection in each sampling stratum. A household listing operation was carried out in all of the selected EAs from September to December 2015. The resulting lists of households served as a sampling frame for the selection of households in the second stage. Some of the selected EAs were large, consisting of more than 300 households. To minimise the task of household listing, each large EA selected for the 2016 EDHS was segmented. Only one segment was selected for the survey with probability proportional to segment size. Household listing was conducted only in the selected segment; that is, a 2016 EDHS cluster is either an EA or a segment of an EA.
In the second stage of selection, a fixed number of 28 households per cluster were selected with an equal probability systematic selection from the newly created household listing. All women age 15-49 and all men age 15-59 who were either permanent residents of the selected households or visitors who stayed in the household the night before the survey were eligible to be interviewed. In half of the selected households, all women age 15-49 were eligible for the FGM/C module, and only one woman per household was selected for the domestic violence module. In all of the selected households, height and weight measurements were collected from children age 0-59 months, women age 15-49, and men age 15-59. Anaemia testing was performed on consenting women age 15-49 and men age 15-59 and on children age 6-59 months whose parent/guardian consented to the testing. In addition, DBS samples were collected for HIV testing in the laboratory from women age 15-49 and men age 15-59 who consented to testing.
Computer Assisted Personal Interview [capi]
Five questionnaires were used for the 2016 EDHS: the Household Questionnaire, the Woman’s Questionnaire, the Man’s Questionnaire, the Biomarker Questionnaire, and the Health Facility Questionnaire. These questionnaires, based on the DHS Program’s standard Demographic and Health Survey questionnaires, were adapted to reflect the population and health issues relevant to Ethiopia. Input was solicited from various stakeholders representing government ministries and agencies, nongovernmental organisations, and international donors. After all questionnaires were finalised in English, they were translated into Amarigna, Tigrigna, and Oromiffa.
The Household Questionnaire was used to list all members of and visitors to selected households. Basic demographic information was collected on the characteristics of each person listed, including his or her age, sex, marital status, education, and relationship to the head of the household. For children under age 18, parents’ survival status was determined. The data on age and sex of household members obtained in the Household Questionnaire were used to identify women and men who were eligible for individual interviews. The Household Questionnaire also collected information on characteristics of the household’s dwelling unit, such as source of water, type of toilet facilities, and flooring materials, as well as on ownership of various durable goods. The Household Questionnaire included an additional module developed by the DHS Program to estimate the prevalence of injuries/accidents among all household members.
The Woman’s Questionnaire was used to collect information from all eligible women age 15-49. These women were asked questions on the following topics: - Background characteristics (including age, education, and media exposure) - Birth history and childhood mortality - Family planning, including knowledge, use, and sources of contraceptive methods - Fertility preferences - Antenatal, delivery, and postnatal care - Breastfeeding and infant feeding practices - Vaccinations and childhood illnesses - Women’s work and husbands’ background characteristics - Knowledge, awareness, and behaviour regarding HIV/AIDS and other sexually transmitted diseases (STDs) - Knowledge, attitudes, and behaviours related to other health issues (e.g., injections, smoking, use of chat) - Adult and maternal mortality - Female genital mutilation or cutting - Fistula - Violence against women The Man’s Questionnaire was administered to all eligible men age 15-59. This questionnaire collected much of the same information elicited from the Woman’s Questionnaire but was shorter because it did not contain a detailed reproductive history, questions on maternal and child health, or questions on domestic violence. The Biomarker Questionnaire was used to record biomarker data
Attribution 4.0 (CC BY 4.0)https://creativecommons.org/licenses/by/4.0/
License information was derived automatically
Ethiopia: Rural population, percent of total population: The latest value from 2023 is 76.84 percent, a decline from 77.34 percent in 2022. In comparison, the world average is 38.64 percent, based on data from 196 countries. Historically, the average for Ethiopia from 1960 to 2023 is 86.6 percent. The minimum value, 76.84 percent, was reached in 2023 while the maximum of 93.57 percent was recorded in 1960.
Attribution 4.0 (CC BY 4.0)https://creativecommons.org/licenses/by/4.0/
License information was derived automatically
The third Population and Housing Census of Ethiopia was conducted in May and November 2007. The census findings are organized by age, sex, religion, ethnicity, region and urban and rural residence. This summary report contains an extract of the census data from this first release and the remaining census results will be disseminated subsequently.
Attribution 4.0 (CC BY 4.0)https://creativecommons.org/licenses/by/4.0/
License information was derived automatically
Ethiopia: Population ages 65 and above, percent of total: The latest value from 2023 is 3.17 percent, an increase from 3.12 percent in 2022. In comparison, the world average is 10.17 percent, based on data from 196 countries. Historically, the average for Ethiopia from 1960 to 2023 is 2.78 percent. The minimum value, 2.61 percent, was reached in 2000 while the maximum of 3.17 percent was recorded in 2023.
Attribution 4.0 (CC BY 4.0)https://creativecommons.org/licenses/by/4.0/
License information was derived automatically
ET: Population: Female: Ages 50-54: % of Female Population data was reported at 2.800 % in 2017. This records an increase from the previous number of 2.766 % for 2016. ET: Population: Female: Ages 50-54: % of Female Population data is updated yearly, averaging 2.913 % from Dec 1960 (Median) to 2017, with 58 observations. The data reached an all-time high of 3.088 % in 1960 and a record low of 2.664 % in 2005. ET: Population: Female: Ages 50-54: % of Female Population data remains active status in CEIC and is reported by World Bank. The data is categorized under Global Database’s Ethiopia – Table ET.World Bank: Population and Urbanization Statistics. Female population between the ages 50 to 54 as a percentage of the total female population.; ; World Bank staff estimates based on age/sex distributions of United Nations Population Division's World Population Prospects: 2017 Revision.; ;
Attribution-ShareAlike 4.0 (CC BY-SA 4.0)https://creativecommons.org/licenses/by-sa/4.0/
License information was derived automatically
This map shows ethnic fractionalization. The Ethnic Fractionalization Index is calculated using data from the 2007 Population and Housing Census. The striped areas show where marginality hotspots are. The map reveals that marginality hotspots are ethnically more homogeneous than non-hotspot areas. Quality/Lineage: This map shows the ethnic fractionalization index as developed by Taylor and Hudson (1970). The index is calculated as 1- sum(gi), where g is the proportion of people belonging to ethnic group i. The sum runs from 1 to n, where n is the number of ethnic groups in the country. The data used is taken from the 2007 Population and Housing Census (CSA, 2008) and is available on woreda (district) level.
Attribution 4.0 (CC BY 4.0)https://creativecommons.org/licenses/by/4.0/
License information was derived automatically
Ethiopia: Percent of world population: The latest value from 2023 is 1.59 percent, an increase from 1.56 percent in 2022. In comparison, the world average is 0.51 percent, based on data from 196 countries. Historically, the average for Ethiopia from 1960 to 2023 is 1.03 percent. The minimum value, 0.72 percent, was reached in 1960 while the maximum of 1.59 percent was recorded in 2023.
Table A, Inheritance model for the fingerprint pattern. 7 genes related to fingerprint patterns. Table B, Allelic Frequencies. Allelic frequencies among the ethnic groups. (DOCX)
Attribution 4.0 (CC BY 4.0)https://creativecommons.org/licenses/by/4.0/
License information was derived automatically
Urban population (% of total population) in Ethiopia was reported at 23.66 % in 2024, according to the World Bank collection of development indicators, compiled from officially recognized sources. Ethiopia - Urban population (% of total) - actual values, historical data, forecasts and projections were sourced from the World Bank on July of 2025.
This statistic shows the age structure in Ethiopia from 2013 to 2023. In 2023, about 39.37 percent of Ethiopia's total population were aged 0 to 14 years.
In 1800, the population of Ethiopia was 2.95 million. Like most other Sub-Saharan countries, Ethiopia experienced slow but steady growth for much of the 18th century, and growth which would increase exponentially as the country entered the 20th century. Ethiopia’s population grew more rapidly as the 20th century progressed, however, this growth was offset in the late 1970s, with the beginning of the Ethiopian Civil War and the coinciding Qey Shibir (Red Terror) campaign. However, despite experiencing a significant famine from 1983 to 1985, which would result in approximately one million deaths, Ethiopia’s population would begin to grow rapidly once more, from 35 million in 1980 to 66 million by the beginning of the 21st century. By 2020, Ethiopia is estimated to have a population of almost 115 million, with some experts predicting that Ethiopia may become one of the most populous countries in the world by 2100.