Between 1821 and 1921, the entire island of Ireland was a part of the United Kingdom of Great Britain and Ireland, after both islands were united by the Act of Union in 1800. This graph shows only the population of the six counties of Ireland that would go on to become Northern Ireland. The population was just under 1.4 million in 1821 and grew to 1.7 million in the next twenty years.

Between 1845 and 1849 the Great Famine devastated the overall population of Ireland, causing the deaths of approximately one million people, and causing a further million to emigrate. Although the famine affected the population of the west and south of Ireland much more severely than the north, the population of the six counties still fell by over 200,000 people between 1841 and 1851. The population then continued to fall, reaching it's lowest point in the 1890s where it was 1.2 million. The Northern Irish population then grows slowly until the mid to late 1900s, during which time the state of Northern Ireland was founded in 1921. The population the reaches over 1.54 million in the 1960s, before it falls again in the 1970s. This drop in population coincides with the outbreak and the most violent decade of the Troubles in Northern Ireland, which was a conflict that dominated Northern Irish daily life for decades. However, from 1981 onwards the population grows by 70,000 to 12,000 every ten years, surpassing it's pre-famine level in the 1990s.

National and subnational mid-year population estimates for the UK and its constituent countries by administrative area, age and sex (including components of population change, median age and population density).

In 2024, Belfast was the local district which had the highest number of inhabitants in Northern Ireland, with an estimated population of 352,390, followed by Armagh City, Banbridge and Craigavon which had approximately 222,511 people living there in this year.

In 1821, the population of the island of Ireland was just over 6.8 million people. During this time, the entire island was a part of the United Kingdom of Great Britain and Ireland, after both islands were united by the Act of Union in 1800. The population enjoyed steady growth between 1821 and 1841, and it rose by almost 1.4 million people in this time, however the Great Famine, which lasted from 1845 to 1849, had a devastating impact on the population, causing it to drop from 8.18 million in 1841 to 6.55 million in 1851. If applying modern-day borders, the population of Northern Ireland was not growing as fast as the population of the Republic of Ireland before 1841, however it was not as severely affected by the famine, which was hardest felt in the east and south. The Great Hunger The famine was caused by a Europe-wide potato blight that contributed to mass starvation and death throughout the continent, although it's impact on Ireland was much harsher than anywhere else. The potato blight affected Ireland so severely as the majority of potatoes in Ireland were of a single variety which allowed the disease to spread much faster than in other countries. As the potato blight spread, the population became increasingly dependent on dairy and grain products, however a lot of these resources were relocated by the British military to combat food shortages in Britain. Due to disproportional dependency on potatoes, and mismanagement by the British government, over one million people died and a further one million emigrated. The Great Famine lasted from just 1845 to 1849, but it's legacy caused almost a century of population decline, and to this day, the overall population of Ireland has never exceeded it's pre-famine levels. Decline continues through partition The population decline continued well into the twentieth century, during which time the Republic of Ireland achieved independence from the British Empire. After centuries of fighting and rebellion against British rule, Irish nationalists finally gained independence from Britain in 1921, although the six counties with the largest Protestant populations formed Northern Ireland, which is still a part of the United Kingdom today. Although there was much conflict in Ireland in the twentieth century which claimed the lives of thousands of people (particularly during the Northern Irish Troubles), and despite Ireland's high emigration rate, the overall population began growing again in the second half of the 1900s. Recovery The population of the Republic of Ireland was at it's lowest in 1961, with 2.8 million people, which is almost four million fewer people than before the famine. Since then it has grown consistently, reaching 4.6 million in 2011 and expected to reach 5 million people by 2020. In Northern Ireland, the population began growing again from the beginning of the 1900s, but growth has been very slow. The only time it fell was in the 1970s, at the peak of The Troubles, where high unemployment and violence contributed to a lower birth rate and an increase in emigration. From the 1980s onwards, living standards improved and the population began growing again, reaching 1.8 million people in 2011.

The island of Ireland is split into 32 different counties, and from 1800 until 1921 the whole island was a part of the United Kingdome of Great Britain and Ireland (although Britain had been a controlling presence on the island for considerably longer than this). In 1921 the island was split into two separate states, where the six counties with the highest population of Protestants formed part of the United Kingdom of Great Britain and Northern Ireland, and the other 26 counties became the Independent Republic of Ireland. From 1821 until 1841, the population of these 26 counties was growing steadily, until the Great Famine from 1845 to 1849 swept across the island, particularly devastating the west and south.

The famine was caused by a Europe-wide potato blight that contributed to mass starvation and death throughout the continent, although it's impact on Ireland was much harsher than anywhere else. The potato blight affected Ireland so severely as the majority of potatoes in Ireland were of a single variety which allowed the disease to spread much faster than in other countries. People in the west and south of Ireland were particularly dependent on potatoes, and these areas were affected more heavily than the north and west, where flax and cereals were the staple. As the potato blight spread, the population became increasingly reliant on dairy and grain products, however a lot of these resources were relocated by the British military to combat food shortages in Britain. Due to disproportional dependency on potatoes, and mismanagement by the British government, over one million people died and a further one million emigrated. The Great Famine lasted from just 1845 to 1849, but it's legacy caused almost a century of population decline, and to this day, the population of Ireland has never exceeded it's pre-famine levels.

The population decline continued well into the twentieth century, during which time the Republic of Ireland achieved independence from the British Empire. After centuries of fighting and rebellion against British rule, Irish nationalists finally gained some independence from Britain in 1921, establishing an Irish Republic in the 26 counties. There was a lot of conflict in Ireland in the early 1900s, through the War of Independence and Irish Civil War, however the population of the Republic began growing again from the 1960s onwards as the quality of life improved and the emigration rate declined. The population was at it's lowest from 1926 to 1971, where it remained at just under three million, but in the following fifty years the population has grown by over two million people.

Usually resident population by place of birth and citizenship by NUTS3. (Census 2022 Theme 2 Table 1 )Census 2022 table 2.1 is the population usually resident in Ireland by birthplace and citizenship. Details include population by place of birth and citizenship. Census 2022 theme 2 is Migration, Ethnicity, Religion and Foreign Languages. The Nomenclature of Territorial Units for Statistics (NUTS) were created by Eurostat in order to define territorial units for the production of regional statistics across the European Union. In 2003 the NUTS classification was established within a legal framework (Regulation (EC) No 1059/2003).Changes made under the 2014 Local Government Act prompted a revision of the Irish NUTS 2 and NUTS 3 Regions. The main changes at NUTS 3 level were the transfer of South Tipperary from the South-East into the Mid-West NUTS 3 region and the movement of Louth from the Border to the Mid-East NUTS 3 Region. NUTS 3 Regions are grouped into three NUTS 2 Regions (Northern and Western, Southern, Eastern and Midland) which correspond to the Regional Assemblies established in the 2014 Local Government Act. The revisions made to the NUTS boundaries have been given legal status under Commission Regulation (EU) 2016/2066.Coordinate reference system: Irish Transverse Mercator (EPSG 2157). These boundaries are based on 20m generalised boundaries sourced from Tailte Éireann Open Data Portal. NUTS3 Regions 2015This dataset is provided by Tailte Éireann

The population of the United Kingdom in 2024 was estimated to be approximately 69.3 million, with over 9.6 million people living in South East England. London had the next highest population, at almost 9.1 million people, followed by the North West England at 7.7 million. With the UK's population generally concentrated in England, most English regions have larger populations than the constituent countries of Scotland, Wales, and Northern Ireland, which had populations of 5.5 million, 3.2 million, and 1.9 million respectively. English counties and cities The United Kingdom is a patchwork of various regional units, within England the largest of these are the regions shown here, which show how London, along with the rest of South East England had around 18 million people living there in this year. The next significant regional units in England are the 47 metropolitan and ceremonial counties. After London, the metropolitan counties of the West Midlands, Greater Manchester, and West Yorkshire were the biggest of these counties, due to covering the large urban areas of Birmingham, Manchester, and Leeds respectively. Regional divisions in Scotland, Wales and Northern Ireland The smaller countries that comprise the United Kingdom each have different local subdivisions. Within Scotland these are called council areas, whereas in Wales the main regional units are called unitary authorities. Scotland's largest Council Area by population is that of Glasgow City at over 650,000, while in Wales, it was the Cardiff Unitary Authority at around 384,000. Northern Ireland, on the other hand, has eleven local government districts, the largest of which is Belfast with a population of approxiamtely 352,000.

Population by sex and marital status by Local Authorities. (Census 2022 Theme 1 Table 2 )Census 2022 table 1.2 is the total population of Ireland by sex and marital status. Details include population by sex and marital status. Census 2022 theme 1 is population by Sex, Age and Marital status. The country is divided into 31 administrative counties/cities. Outside Dublin, there are 23 administrative counties and four cities: Cork, Limerick, Waterford and Galway. There are four local authority areas in Dublin: Dublin City and the three administrative counties of Dún Laoghaire-Rathdown, Fingal and South Dublin. The Local Government Reform Act 2014 Section 9 provided for the amalgamation of the city and county councils in Limerick, Waterford, and North Tipperary and South Tipperary County Councils.Coordinate reference system: Irish Transverse Mercator (EPSG 2157). These boundaries are based on 20m generalised boundaries sourced from Tailte Éireann Open Data Portal. This dataset is provided by Tailte Éireann, Administrative Counties 2019

This data is experimental, see the ‘Access Constraints or User Limitations’ section for more details. This dataset has been generalised to 10 metre resolution where it is still but the space needed for downloads will be improved.A set of UK wide estimated travel area geometries (isochrones), from Output Area (across England, Scotland, and Wales) and Small Area (across Northern Ireland) population-weighted centroids. The modes used in the isochrone calculations are limited to public transport and walking. Generated using Open Trip Planner routing software in combination with Open Street Maps and open public transport schedule data (UK and Ireland).The geometries provide an estimate of reachable areas by public transport and on foot between 7:15am and 9:15am for a range of maximum travel durations (15, 30, 45 and 60 minutes). For England, Scotland and Wales, these estimates were generated using public transport schedule data for Tuesday 15th November 2022. For Northern Ireland, the date used is Tuesday 6th December 2022.The data is made available as a set of ESRI shape files, in .zip format. This corresponds to a total of 18 files; one for Northern Ireland, one for Wales, twelve for England (one per English region, where London, South East and North West have been split into two files each) and four for Scotland (one per NUTS2 region, where the ‘North-East’ and ‘Highlands and Islands’ have been combined into one shape file, and South West Scotland has been split into two files).The shape files contain the following attributes. For further details, see the ‘Access Constraints or User Limitations’ section:AttributeDescriptionOA21CD or SA2011 or OA11CDEngland and Wales: The 2021 Output Area code.Northern Ireland: The 2011 Small Area code.Scotland: The 2011 Output Area code.centre_latThe population-weighted centroid latitude.centre_lonThe population-weighted centroid longitude.node_latThe latitude of the nearest Open Street Map “highway” node to the population-weighted centroid.node_lonThe longitude of the nearest Open Street Map “highway” node to the population-weighted centroid.node_distThe distance, in meters, between the population-weighted centroid and the nearest Open Street Map “highway” node.stop_latThe latitude of the nearest public transport stop to the population-weighted centroid.stop_lonThe longitude of the nearest public transport stop to the population-weighted centroid.stop_distThe distance, in metres, between the population-weighted centroid and the nearest public transport stop.centre_inBinary value (0 or 1), where 1 signifies the population-weighted centroid lies within the Output Area/Small Area boundary. 0 indicates the population-weighted centroid lies outside the boundary.node_inBinary value (0 or 1), where 1 signifies the nearest Open Street Map “highway” node lies within the Output Area/Small Area boundary. 0 indicates the nearest Open Street Map node lies outside the boundary.stop_inBinary value (0 or 1), where 1 signifies the nearest public transport stop lies within the Output Area/Small Area boundary. 0 indicates the nearest transport stop lies outside the boundary.iso_cutoffThe maximum travel time, in seconds, to construct the reachable area/isochrone. Values are either 900, 1800, 2700, or 3600 which correspond to 15, 30, 45, and 60 minute limits respectively.iso_dateThe date for which the isochrones were estimated, in YYYY-MM-DD format.iso_typeThe start point from which the estimated isochrone was calculated. Valid values are:from_centroid: calculated using population weighted centroid.from_node: calculated using the nearest Open Street Map “highway” node.from_stop: calculated using the nearest public transport stop.no_trip_found: no isochrone was calculated.geometryThe isochrone geometry.iso_hectarThe area of the isochrone, in hectares.Access constraints or user limitations.These data are experimental and will potentially have a wider degree of uncertainty. They remain subject to testing of quality, volatility, and ability to meet user needs. The methodologies used to generate them are still subject to modification and further evaluation.These experimental data have been published with specific caveats outlined in this section. The data are shared with the analytical community with the purpose of benefitting from the community's scrutiny and in improving the quality and demand of potential future releases. There may be potential modification following user feedback on both its quality and suitability.For England and Wales, where possible, the latest census 2021 Output Area population weighted centroids were used as the starting point from which isochrones were calculated.For Northern Ireland, 2011 Small Area population weighted centroids were used as the starting point from which isochrones were calculated. Small Areas and Output Areas contain a similar number of households within their boundaries. 2011 data was used because this was the most up-to-date data available at the time of generating this dataset. Population weighted centroids for Northern Ireland were calculated internally but may be subject to change - in the future we aim to update these data to be consistent with Census 2021 across the UK.For Scotland, 2011 Output Area population-weighted centroids were used as the starting point from which isochrones were calculated. 2011 data was used because this was the most up-to-date data available at the time of work.The data for England, Scotland and Wales are released with the projection EPSG:27700 (British National Grid).The data for Northern Ireland are released with the projection EPSG:29902 (Irish Grid).The modes used in the isochrone calculations are limited to public transport and walking. Other modes were not considered when generating this data.A maximum value of 1.5 kilometres walking distance was used when generating isochrones. This approximately represents typical walking distances during a commute (based on Department for Transport/Labour Force Survey data and Travel Survey for Northern Ireland technical reports).When generating Northern Ireland data, public transport schedule data for both Northern Ireland and Republic of Ireland were used.Isochrone geometries and calculated areas are subject to public transport schedule data accuracy, Open Trip Planner routing methods and Open Street Map accuracy. The location of the population-weighted centroid can also influence the validity of the isochrones, when this falls on land which is not possible or is difficult to traverse (e.g., private land and very remote locations).The Northern Ireland public transport data were collated from several files, and as such required additional pre-processing. Location data are missing for two bus stops. Some services run by local public transport providers may also be missing. However, the missing data should have limited impact on the isochrone output. Due to the availability of Northern Ireland public transport data, the isochrones for Northern Ireland were calculated on a comparable but slight later date of 6th December 2022. Any potential future releases are likely to contained aligned dates between all four regions of the UK.In cases where isochrones are not calculable from the population-weighted centroid, or when the calculated isochrones are unrealistically small, the nearest Open Street Map ‘highway’ node is used as an alternative starting point. If this then fails to yield a result, the nearest public transport stop is used as the isochrone origin. If this also fails to yield a result, the geometry will be ‘None’ and the ‘iso_hectar’ will be set to zero. The following information shows a further breakdown of the isochrone types for the UK as a whole:from_centroid: 99.8844%from_node: 0.0332%from_stop: 0.0734%no_trip_found: 0.0090%The term ‘unrealistically small’ in the point above refers to outlier isochrones with a significantly smaller area when compared with both their neighbouring Output/Small Areas and the entire regional distribution. These reflect a very small fraction of circumstances whereby the isochrone extent was impacted by the centroid location and/or how Open Trip Planner handled them (e.g. remote location, private roads and/or no means of traversing the land). Analysis showed these outliers were consistently below 100 hectares for 60-minute isochrones. Therefore, In these cases, the isochrone point of origin was adjusted to the nearest node or stop, as outlined above.During the quality assurance checks, the extent of the isochrones was observed to be in good agreement with other routing software and within the limitations stated within this section. Additionally, the use of nearest node, nearest stop, and correction of ‘unrealistically small areas’ was implemented in a small fraction of cases only. This culminates in no data being available for 8 out of 239,768 Output/Small Areas.Data is only available in ESRI shape file format (.zip) at this release.https://www.openstreetmap.org/copyright

Original provider: National Parks and Wildlife Service, Dept. of Environment, Heritage and Local Government

Dataset credits: National Parks and Wildlife Service, Dept. of Environment, Heritage and Local Government
Michelle Cronin, Coastal & Marine Resources Centre, University College Cork

Abstract: The status of Ireland's harbor seal Phoca vitulina vitulina population is poorly understood. The most recent national population estimate dates back to the breeding season in 1978 and did not cover the entire coastline. Reliable up-to-date information on the abundance and distribution of harbor seals in Ireland is necessary to assess the conservation status of the species and for the effective identification, management and monitoring of special areas of conservation required for harbor seals under the European Union Habitats Directive. To provide comprehensive current information on Ireland's harbor seal population, a geographically extensive survey was conducted along the coastline of the Republic of Ireland during the species' annual moult in August 2003. This complemented a similar survey of Northern Ireland, which was conducted in 2002. Using thermal imaging technology, haul-out groups of harbor seals and grey seals Halichoerus grypus were identified from the air, aerial-counts were obtained and compared with simultaneous ground-count data from selected sites. Harbor seal distribution recorded during the 2003 moult season was concentrated in the south-west, west and north-west of the country. This national survey yielded a minimum population estimate for the Republic of Ireland of 2905 harbor seals, delivering an effective baseline for current and future population research.

This feature layer was created using Census 2016 data produced by the Central Statistics Office (CSO) and Administrative Counties national boundary data (generalised to 50m) produced by Tailte Éireann. The layer represents Census 2016 theme 11.2, population aged 5+ by time leaving home to travel to work, school or college. Attributes include a breakdown of population by time leaving for work, school or college (e.g. 6.30 - 7.00, 8.30 - 9.00). Census 2016 theme 11 represents Commuting. The Census is carried out every five years by the CSO to determine an account of every person in Ireland. The results provide information on a range of themes, such as, population, housing and education. The data were sourced from the CSO. In census reports the country is divided into 29 counties/administrative counties and the five Cities which represent the local authority areas. Outside Dublin there are 26 administrative counties (North Tipperary and South Tipperary each ranks as a separate county for administrative purposes) and four Cities, i.e. Cork, Limerick, Waterford and Galway. In Dublin the four local authority areas are identified separately, i.e. Dublin City and the three administrative counties of Dún Laoghaire-Rathdown, Fingal and South Dublin.

Abstract

Different countries have different health outcomes that are in part due to the way respective health systems perform. Regardless of the type of health system, individuals will have health and non-health expectations in terms of how the institution responds to their needs. In many countries, however, health systems do not perform effectively and this is in part due to lack of information on health system performance, and on the different service providers.

The aim of the WHO World Health Survey is to provide empirical data to the national health information systems so that there is a better monitoring of health of the people, responsiveness of health systems and measurement of health-related parameters.

The overall aims of the survey is to examine the way populations report their health, understand how people value health states, measure the performance of health systems in relation to responsiveness and gather information on modes and extents of payment for health encounters through a nationally representative population based community survey. In addition, it addresses various areas such as health care expenditures, adult mortality, birth history, various risk factors, assessment of main chronic health conditions and the coverage of health interventions, in specific additional modules.

The objectives of the survey programme are to: 1. develop a means of providing valid, reliable and comparable information, at low cost, to supplement the information provided by routine health information systems. 2. build the evidence base necessary for policy-makers to monitor if health systems are achieving the desired goals, and to assess if additional investment in health is achieving the desired outcomes. 3. provide policy-makers with the evidence they need to adjust their policies, strategies and programmes as necessary.

Geographic coverage

The survey sampling frame must cover 100% of the country's eligible population, meaning that the entire national territory must be included. This does not mean that every province or territory need be represented in the survey sample but, rather, that all must have a chance (known probability) of being included in the survey sample.

There may be exceptional circumstances that preclude 100% national coverage. Certain areas in certain countries may be impossible to include due to reasons such as accessibility or conflict. All such exceptions must be discussed with WHO sampling experts. If any region must be excluded, it must constitute a coherent area, such as a particular province or region. For example if ¾ of region D in country X is not accessible due to war, the entire region D will be excluded from analysis.

Analysis unit

Households and individuals

Universe

The WHS will include all male and female adults (18 years of age and older) who are not out of the country during the survey period. It should be noted that this includes the population who may be institutionalized for health reasons at the time of the survey: all persons who would have fit the definition of household member at the time of their institutionalisation are included in the eligible population.

If the randomly selected individual is institutionalized short-term (e.g. a 3-day stay at a hospital) the interviewer must return to the household when the individual will have come back to interview him/her. If the randomly selected individual is institutionalized long term (e.g. has been in a nursing home the last 8 years), the interviewer must travel to that institution to interview him/her.

The target population includes any adult, male or female age 18 or over living in private households. Populations in group quarters, on military reservations, or in other non-household living arrangements will not be eligible for the study. People who are in an institution due to a health condition (such as a hospital, hospice, nursing home, home for the aged, etc.) at the time of the visit to the household are interviewed either in the institution or upon their return to their household if this is within a period of two weeks from the first visit to the household.

Kind of data

Sample survey data [ssd]

Sampling procedure

SAMPLING GUIDELINES FOR WHS

Surveys in the WHS program must employ a probability sampling design. This means that every single individual in the sampling frame has a known and non-zero chance of being selected into the survey sample. While a Single Stage Random Sample is ideal if feasible, it is recognized that most sites will carry out Multi-stage Cluster Sampling.

The WHS sampling frame should cover 100% of the eligible population in the surveyed country. This means that every eligible person in the country has a chance of being included in the survey sample. It also means that particular ethnic groups or geographical areas may not be excluded from the sampling frame.

The sample size of the WHS in each country is 5000 persons (exceptions considered on a by-country basis). An adequate number of persons must be drawn from the sampling frame to account for an estimated amount of non-response (refusal to participate, empty houses etc.). The highest estimate of potential non-response and empty households should be used to ensure that the desired sample size is reached at the end of the survey period. This is very important because if, at the end of data collection, the required sample size of 5000 has not been reached additional persons must be selected randomly into the survey sample from the sampling frame. This is both costly and technically complicated (if this situation is to occur, consult WHO sampling experts for assistance), and best avoided by proper planning before data collection begins.

All steps of sampling, including justification for stratification, cluster sizes, probabilities of selection, weights at each stage of selection, and the computer program used for randomization must be communicated to WHO

STRATIFICATION

Stratification is the process by which the population is divided into subgroups. Sampling will then be conducted separately in each subgroup. Strata or subgroups are chosen because evidence is available that they are related to the outcome (e.g. health, responsiveness, mortality, coverage etc.). The strata chosen will vary by country and reflect local conditions. Some examples of factors that can be stratified on are geography (e.g. North, Central, South), level of urbanization (e.g. urban, rural), socio-economic zones, provinces (especially if health administration is primarily under the jurisdiction of provincial authorities), or presence of health facility in area. Strata to be used must be identified by each country and the reasons for selection explicitly justified.

Stratification is strongly recommended at the first stage of sampling. Once the strata have been chosen and justified, all stages of selection will be conducted separately in each stratum. We recommend stratifying on 3-5 factors. It is optimum to have half as many strata (note the difference between stratifying variables, which may be such variables as gender, socio-economic status, province/region etc. and strata, which are the combination of variable categories, for example Male, High socio-economic status, Xingtao Province would be a stratum).

Strata should be as homogenous as possible within and as heterogeneous as possible between. This means that strata should be formulated in such a way that individuals belonging to a stratum should be as similar to each other with respect to key variables as possible and as different as possible from individuals belonging to a different stratum. This maximises the efficiency of stratification in reducing sampling variance.

MULTI-STAGE CLUSTER SELECTION

A cluster is a naturally occurring unit or grouping within the population (e.g. enumeration areas, cities, universities, provinces, hospitals etc.); it is a unit for which the administrative level has clear, nonoverlapping boundaries. Cluster sampling is useful because it avoids having to compile exhaustive lists of every single person in the population. Clusters should be as heterogeneous as possible within and as homogenous as possible between (note that this is the opposite criterion as that for strata). Clusters should be as small as possible (i.e. large administrative units such as Provinces or States are not good clusters) but not so small as to be homogenous.

In cluster sampling, a number of clusters are randomly selected from a list of clusters. Then, either all members of the chosen cluster or a random selection from among them are included in the sample. Multistage sampling is an extension of cluster sampling where a hierarchy of clusters are chosen going from larger to smaller.

In order to carry out multi-stage sampling, one needs to know only the population sizes of the sampling units. For the smallest sampling unit above the elementary unit however, a complete list of all elementary units (households) is needed; in order to be able to randomly select among all households in the TSU, a list of all those households is required. This information may be available from the most recent population census. If the last census was >3 years ago or the information furnished by it was of poor quality or unreliable, the survey staff will have the task of enumerating all households in the smallest randomly selected sampling unit. It is very important to budget for this step if it is necessary and ensure that all households are properly enumerated in order that a representative sample is obtained.

It is always best to have as many clusters in the PSU as possible. The reason for this is that the fewer the number of respondents in each PSU, the lower will be the clustering effect which

In 2021, there were **** births per 1,000 people in Northern Ireland, compared with eleven in the previous year. Between 2000 and 2008, Northern Ireland's birth rate increased from **** to **** but started to decline gradually until 2012 when it dropped from **** to **** in just one year. During this provided time period, the birth rate in Northern Ireland was highest in 1971, when it was **** and was at its lowest in 2020 when there were just eleven births per 1,000 people. Falling birth rates in the UK For the United Kingdom as a whole, the birth rate fell to **** births per 1,000 people in 2020, before a slight uptick to **** in 2021. After a postwar peak of **** births per 1,000 people in 1964, the UK birth rate fell sharply to just **** by 1977. Between 1977 and 2012 the birth rate fluctuated between **** and ****, but declined in every year between 2012 and 2020. In 2021, the UK's fertility rate (the number of births per women) fell to just ****, compared with **** in 1964. Since 1973, the UK has fallen below the minimum replacement level fertility rate of ***, and without immigration would likely see its population decline in the long term. Global demographic trends The considerable decline in the UK's fertility rate in recent decades is not an isolated phenomenon. As of 2025, Africa was, at ****, the only continent to have a fertility rate higher than the global average of ****. Several countries, mainly in East Asia and Europe, have far lower fertility rates than the UK or the global average, however. South Korea provides the most dramatic example of this trend, with its fertility rate falling from **** in 1960 to just **** by 2020. By the *****, it is expected that, as Africa's fertility rate converges with the rest of the world, the global population will peak at around **** billion and start to decline.

The shape files contain the following attributes. For further details, see the ‘Access Constraints or User Limitations’ section:AttributeDescriptionOA21CD or SA2011 or OA11CDEngland and Wales: The 2021 Output Area code.Northern Ireland: The 2011 Small Area code.Scotland: The 2011 Output Area code.centre_latThe population-weighted centroid latitude.centre_lonThe population-weighted centroid longitude.node_latThe latitude of the nearest Open Street Map “highway” node to the population-weighted centroid.node_lon

Alcyonium digitatum microsatellite dataAlcyonium digitatum microsatellite data. Excel file. Data for 8 loci in 2 column format, 648 individuals, 20 sites.Alcyonium_digitatum_Genalex_Heredity.xlsxEunicella verrucosa microsatellite dataEunicella verrucosa microsatellite data. Excel file. Data for 13 loci in 2 column format, 905 individuals, 27 sites.Eunicella_verrucosa_Genalex_Heredity.xlsx

In the past four centuries, the population of the Thirteen Colonies and United States of America has grown from a recorded 350 people around the Jamestown colony in Virginia in 1610, to an estimated 346 million in 2025. While the fertility rate has now dropped well below replacement level, and the population is on track to go into a natural decline in the 2040s, projected high net immigration rates mean the population will continue growing well into the next century, crossing the 400 million mark in the 2070s. Indigenous population Early population figures for the Thirteen Colonies and United States come with certain caveats. Official records excluded the indigenous population, and they generally remained excluded until the late 1800s. In 1500, in the first decade of European colonization of the Americas, the native population living within the modern U.S. borders was believed to be around 1.9 million people. The spread of Old World diseases, such as smallpox, measles, and influenza, to biologically defenseless populations in the New World then wreaked havoc across the continent, often wiping out large portions of the population in areas that had not yet made contact with Europeans. By the time of Jamestown's founding in 1607, it is believed the native population within current U.S. borders had dropped by almost 60 percent. As the U.S. expanded, indigenous populations were largely still excluded from population figures as they were driven westward, however taxpaying Natives were included in the census from 1870 to 1890, before all were included thereafter. It should be noted that estimates for indigenous populations in the Americas vary significantly by source and time period. Migration and expansion fuels population growth The arrival of European settlers and African slaves was the key driver of population growth in North America in the 17th century. Settlers from Britain were the dominant group in the Thirteen Colonies, before settlers from elsewhere in Europe, particularly Germany and Ireland, made a large impact in the mid-19th century. By the end of the 19th century, improvements in transport technology and increasing economic opportunities saw migration to the United States increase further, particularly from southern and Eastern Europe, and in the first decade of the 1900s the number of migrants to the U.S. exceeded one million people in some years. It is also estimated that almost 400,000 African slaves were transported directly across the Atlantic to mainland North America between 1500 and 1866 (although the importation of slaves was abolished in 1808). Blacks made up a much larger share of the population before slavery's abolition. Twentieth and twenty-first century The U.S. population has grown steadily since 1900, reaching one hundred million in the 1910s, two hundred million in the 1960s, and three hundred million in 2007. Since WWII, the U.S. has established itself as the world's foremost superpower, with the world's largest economy, and most powerful military. This growth in prosperity has been accompanied by increases in living standards, particularly through medical advances, infrastructure improvements, clean water accessibility. These have all contributed to higher infant and child survival rates, as well as an increase in life expectancy (doubling from roughly 40 to 80 years in the past 150 years), which have also played a large part in population growth. As fertility rates decline and increases in life expectancy slows, migration remains the largest factor in population growth. Since the 1960s, Latin America has now become the most common origin for migrants in the U.S., while immigration rates from Asia have also increased significantly. It remains to be seen how immigration restrictions of the current administration affect long-term population projections for the United States.

This data is experimental, see the ‘Access Constraints or User Limitations’ section for more details. This dataset has been generalised to 10 metre resolution where it is still but the space needed for downloads will be improved.

A set of UK wide estimated travel area geometries (isochrones), from Output Area (across England, Scotland, and Wales) and Small Area (across Northern Ireland) population-weighted centroids. The modes used in the isochrone calculations are limited to public transport and walking. Generated using Open Trip Planner routing software in combination with Open Street Maps and open public transport schedule data (UK and Ireland).

The geometries provide an estimate of reachable areas by public transport and on foot between 7:15am and 9:15am for a range of maximum travel durations (15, 30, 45 and 60 minutes). For England, Scotland and Wales, these estimates were generated using public transport schedule data for Tuesday 15th November 2022. For Northern Ireland, the date used is Tuesday 6th December 2022.

The data is made available as a set of ESRI shape files, in .zip format. This corresponds to a total of 18 files; one for Northern Ireland, one for Wales, twelve for England (one per English region, where London, South East and North West have been split into two files each) and four for Scotland (one per NUTS2 region, where the ‘North-East’ and ‘Highlands and Islands’ have been combined into one shape file, and South West Scotland has been split into two files).

The shape files contain the following attributes. For further details, see the ‘Access Constraints or User Limitations’ section:

Usually resident population aged 1 year and over by usual residence 1 year before Census Day by Local Authorities. (Census 2022 Theme 2 Table 3 )Census 2022 table 2.3 is the population usually resident in Ireland by usual residence 1 year before Census Day. Details include population by usual residence 1 year before Census Day. Census 2022 theme 2 is Migration, Ethnicity, Religion and Foreign Languages. The country is divided into 31 administrative counties/cities. Outside Dublin, there are 23 administrative counties and four cities: Cork, Limerick, Waterford and Galway. There are four local authority areas in Dublin: Dublin City and the three administrative counties of Dún Laoghaire-Rathdown, Fingal and South Dublin. The Local Government Reform Act 2014 Section 9 provided for the amalgamation of the city and county councils in Limerick, Waterford, and North Tipperary and South Tipperary County Councils.Coordinate reference system: Irish Transverse Mercator (EPSG 2157). These boundaries are based on 20m generalised boundaries sourced from Tailte Éireann Open Data Portal. This dataset is provided by Tailte Éireann, Administrative Counties 2019

As of 2024, the population density in London was by far the highest number of people per square km in the UK, at *****. Of the other regions and countries which constitute the United Kingdom, North West England was the next most densely populated area at *** people per square kilometer. Scotland, by contrast, is the most sparsely populated country or region in the United Kingdom, with only ** people per square kilometer. Countries, regions, and cities In 2024, the population of the United Kingdom reached **** million. The majority of people in the UK live in England, which had a population of **** million that year, followed by Scotland at *** million, Wales at **** million and finally Northern Ireland at just over *** million. Within England, the South East was the region with the highest population at almost *** million, followed by London at just over *****million. In terms of cities, London is the largest urban agglomeration in the United Kingdom, followed by Manchester, and then Birmingham, although both these cities combined would still have a smaller population than the UK capital. London calling London's huge size in relation to other UK cities is also reflected by its economic performance. In 2023, London's GDP was over ****billion British pounds, around a quarter of UK's overall GDP. In terms of GDP per capita, Londoners had a GDP per head of ****** pounds, compared with an average of ****** for the country as a whole. Productivity, expressed as by output per hour worked, was also far higher in London than the rest of the country. In 2023, London was around *****percent more productive than the rest of the country, with South East England the only other region where productivity was higher than the national average.

This data is experimental, see the ‘Access Constraints or User Limitations’ section for more details. This dataset has been generalised to 10 metre resolution where it is still but the space needed for downloads will be improved.

A set of UK wide estimated travel area geometries (isochrones), from Output Area (across England, Scotland, and Wales) and Small Area (across Northern Ireland) population-weighted centroids. The modes used in the isochrone calculations are limited to public transport and walking. Generated using Open Trip Planner routing software in combination with Open Street Maps and open public transport schedule data (UK and Ireland).

The geometries provide an estimate of reachable areas by public transport and on foot between 7:15am and 9:15am for a range of maximum travel durations (15, 30, 45 and 60 minutes). For England, Scotland and Wales, these estimates were generated using public transport schedule data for Tuesday 15th November 2022. For Northern Ireland, the date used is Tuesday 6th December 2022.

The data is made available as a set of ESRI shape files, in .zip format. This corresponds to a total of 18 files; one for Northern Ireland, one for Wales, twelve for England (one per English region, where London, South East and North West have been split into two files each) and four for Scotland (one per NUTS2 region, where the ‘North-East’ and ‘Highlands and Islands’ have been combined into one shape file, and South West Scotland has been split into two files).

The shape files contain the following attributes. For further details, see the ‘Access Constraints or User Limitations’ section: