Updated: 21 January 2021

Next update: 3 May 2023

Proportion of the population 45-49 years who live in cohabitation
Proportion of the population 45-49 years who live in cohabitation

About the statistics

Percentage of cohabitants in the population aged 16-79 years.


The statistics is based on a sample of all persons between 16-79 years who was resident in Norway according to the population register.


Two persons who lives in the same residence and is married to each other, registered partners or cohabiting is counted as a couple.

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Name: Cohabitants
Topic: Population

3 May 2023

Division for Population Statistics


Every third year

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Files on individual level containing data that are processed and stored in the long term.

The statistics is based on surveys and place of usual residence for women and men aged 16-79 years. It shows proportions of cohabitants, married and singles in different age groups. The first figures published are from 1977 for women and 1988 for men. Since 1993 annual figures have been published.

The statistics have a wide range of users and applications, including institutes involved in researching demographics and living conditions, public administration, the mass media and private persons.

No external users have access to the statistics and analyses before they are published and accessible simultaneously for all users on at 08 am. Prior to this, a minimum of three months' advance notice is given inthe Statistics Release Calendar. This is one of Statistics Norway’s key principles for ensuring that all users are treated equally.

The statistics is based on a survey and whether a person is defined as a cohabitant or not depends on what answer the person himself gives to this question. In register based statistic one must be registered on the same legal residence address to be defined as cohabitants. Experience shows that statistics based on registers and legal residence address result in fewer cohabiting couples than statistics from surveys based on interviews and place of usual residence.

Statistics Act § 10

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The statistics cover a sample of the Norwegian population in the age group 16 - 79 years.

The sources for this statistics are the Population register in combination with the Travel survey.

The Travel survey is carried out among 8 000 Norwegians between 16 and 79 years of age, according to Statistics Norway's standard sampling procedure.

Interview (telephone)/CATI

A computer is used during the interview. The interviewer reads the questions aloud from the screen and the answers are registered instantly. This allows the data to be controlled immediately, and it reduces the risk of asking the interviewee wrong questions.

The proportion of cohabitants in an age group is estimated by the number of people in an age group who have answered that they are cohabitants compared to everyone who has answered the questions on relationship status in the same age group. The proportion who are married/not in a relationship are calculated in the same way.

The total number of cohabitants is estimated by multiplying the estimated proportion of cohabitants in an age group by the mean population in the same age group.

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From 2005 data from Statistics Norway's Travel survey has been used. Former sources have been the Fertility survey 1977, Family and Occupation Survey 1988 and Omnibus Surveys 1993-2004. The questions have been the same in all surveys. It is expected that use of data from different surveys do not influence the comparability in the time series.

Collection errors, like when the interviewee gives incorrect information, or processing errors, like when the interviewer registers the answer incorrectly, are tried kept to a minimum by automatically controlling the answers during the interview. Nevertheless, there may still be some errors left. The number and kind of errors are not known.

The unit non-response has inceased somewhat over the years, and is approximately 40 per cent. Non-response errors are errors caused by unit non-response, i.e. that the unit (for instance an individual or a company) has failed to respond, or item non-response, i.e. that the unit has failed to respond to some but not all the questions in the survey.

Sampling bias may arise when the distribution of some variables in the sample is not the same as the corresponding distribution in the population. The results in this survey are based on the information provided by those responding. Non-response is mainly due to the interviewee not wanting to participate or that he/she was not reached by the interviewer. If the interviewee was not reached due to he/she being on holiday, the distribution of this variable among those interviewed and the non-respondents may differ and sampling bias may arise.

The Travel survey is carried out among a sample of persons resident in Norway between 16 and 79 years of age. The uncertainty of findings based on only a part of the population, (sampling variance) depends among other factors on the number of observations in the sample and on the distribution of the current variable in the whole population. An estimate of this uncertainty (standard deviation) can be constructed by means of the observations in the sample. There is not made an exact calculation of the standard deviation for this survey.

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