Usually resident population: All persons resident in the State, for a period that is, or is expected to be at least 12 months. Persons who are usually resident in Ireland but are temporarily away from home and outside the State on Census night are included in the usually resident population.
Age specific fertility rate: The age specific fertility rate for a particular age group is the number of live births to women in that age group per 1,000 females in the same age group.
Total fertility rate (TFR): The TFR represents the theoretical average number of children who would be born alive to a woman during her lifetime if she were to pass through her child bearing years (ages 15 - 49) conforming to the age specific fertility rates of a given year. The rate refers to a theoretical female cohort. The TFR is compiled by summing the age specific fertility rates for the relevant five-year age groups, dividing by 1,000 and multiplying by 5. The small number of births for which the age of the mother is not stated is distributed in proportion to the stated categories.
Life expectancy: The average number of additional years a person would live if current mortality trends were to continue. The expectation of life at birth represents the mean length of life of individuals who are subjected since birth to current mortality trends. Life expectancy is usually compiled on the basis of a life table showing the probability of dying at each age for a given population according to the age specific death rates prevailing in a given period.
Survivorship ratio: The survivorship ratio at age x, Sx, is calculated as Sx=Lx/Lx-1 where Lx is the population aged between x and x+1 assuming that 100,000 births occur each year according to the Life Tables.
Immigration: The action by which a person establishes his or her usual residence in the State for a period that is, or is expected to be, of at least 12 months, having previously been usually resident in another Member State or a third country.
Emigration: The action by which a person, having previously been usually resident in the State, ceases to have his or her usual residence in the State for a period that is, or is expected to be, of at least 12 months.
Net migration: The net effect of immigration and emigration. A positive entry denotes that inward migration exceeds outward migration and vice-versa.
Labour force participation rate: The number of persons at work or unemployed (either looking for first regular job or having lost or given up previous job) in a particular age group expressed as a percentage of all persons in that age group.
Young dependency ratio: The population aged 0 - 14 years expressed as a percentage of the population aged 15 - 64 years.
Old dependency ratio: The population aged 65 years and over expressed as a percentage of the population aged 15 - 64 years.
Total dependency ratio: The sum of the young and old dependency ratios.