The mid-year estimates refer to the population on 30 June of the reference year and are produced in line with the standard United Nations (UN) definition for population estimates. They are the official set of population estimates for the UK and its constituent countries, the regions and counties of England, and local authorities and their equivalents.

Historical chart and dataset showing total population for the United Kingdom by year from 1950 to 2025.

The dataset was originally created to allow the construction of age-specific mortality series and cohort mortality series for particular diseases, from the mid-nineteenth century to the present (in conjunction with the comparable mortality database created by the Office of National Statistics which covers 1901 – present). The dataset is fairly comprehensive and therefore allows both fine analysis of trends in single causes and also the construction of consistent aggregated categories of causes over time. Additionally, comparison of trends in individual causes can be used to infer transfers of deaths between categories over time, that may cause artifactual changes in mortality rates of particular causes. The data are presented by sex, allowing calculation of sex ratios. The age-specific and annual nature of the dataset allows the analysis of cause-specific mortality by birth cohort (assuming low migration at the national level). The database can be used in conjunction with the ONS database “Historic Mortality and Population Data, 1901-1992”, already in the UK Data Archive collection as SN 2902, to create continuous cause-of-death series for the period 1848-1992 (or later, if using more recent versions of the ONS database).

As of July 2024, Nigeria's population was estimated at around 229.5 million. Between 1965 and 2024, the number of people living in Nigeria increased at an average rate of over two percent. In 2024, the population grew by 2.42 percent compared to the previous year. Nigeria is the most populous country in Africa. By extension, the African continent records the highest growth rate in the world. Africa's most populous country Nigeria was the most populous country in Africa as of 2023. As of 2022, Lagos held the distinction of being Nigeria's biggest urban center, a status it also retained as the largest city across all of sub-Saharan Africa. The city boasted an excess of 17.5 million residents. Notably, Lagos assumed the pivotal roles of the nation's primary financial hub, cultural epicenter, and educational nucleus. Furthermore, Lagos was one of the largest urban agglomerations in the world. Nigeria's youthful population In Nigeria, a significant 50 percent of the populace is under the age of 19. The most prominent age bracket is constituted by those up to four years old: comprising 8.3 percent of men and eight percent of women as of 2021. Nigeria boasts one of the world's most youthful populations. On a broader scale, both within Africa and internationally, Niger maintains the lowest median age record. Nigeria secures the 20th position in global rankings. Furthermore, the life expectancy in Nigeria is an average of 62 years old. However, this is different between men and women. The main causes of death have been neonatal disorders, malaria, and diarrheal diseases.

Historical chart and dataset showing U.K. death rate by year from 1950 to 2025.