[7] Population structure
These statistics on the structure of the population describe Finnish and foreign citizens permanently resident in Finland at the turn of the year.

Divorce
The divorce statistics are based on data on granted decrees of divorce transmitted to the Population Register Centre by courts of law. The statistics also include cases where a permanent resident of Finland is granted a divorce by a foreign court. If the divorce is granted abroad, it must be reported to the register keeper for registration of divorce. Exceptions are divorces granted to Finnish citizens in Sweden, on which the Swedish register keeper notifies the Finnish counterpart directly.
A divorce granted to a Finnish citizen abroad usually requires validation by the Helsinki Court of Appeal before registration. Divorce decisions given in the Nordic Countries and in the EU countries as of 1 March 2001 can be registered without validation.
In 1980 to 2016, divorces referred to divorces of women living permanently in Finland unless otherwise stated. Starting from the statistical reference year 2017, divorces where at least one of the spouses has resided permanently in Finland on the day the divorce was granted are included in the statistics as divorces. The amendment to the Marriage Act that entered into force on 1 March 2017 enabled same-sex couples to enter into marriage (156/2015). Since 2017, the total number of divorces consists of the number of divorces of marriages between opposite-sex and same-sex couples.
The amendment to the Marriage Act (411/1987), effective from 1 January 1988, simplified divorce proceedings. Divorce figures began to rise towards the end of 1988, when the first divorces (after a reconsideration period of six months) became effective under the new legislation. The Marriage Act no longer has regulations on 'cancellation of marriage' or 'nullification of marriage'. Before the new act came into force in 1988 these were in separate groups, now among divorces.

Marital status
The information on marital status is derived from the Population Information System of the Population Register Centre. It should be noted that common-law marriage or cohabiting is not a marital status. People representing all marital status categories may be cohabiting, including those who are still officially married.
The current divorce regulations no longer recognise the concept of legal separation. Those persons who are legally separated on the basis of the old divorce provisions prior to 1 January 1988 and still living apart have been slotted under married persons in the statistics.
The possibility to register partnerships started in Finland on 1 March 2002 and ended on the last day of February 2017 (Act to amend the Act of Registered Partnerships 250/2016). Starting from the beginning of March 2017, same-sex couples have been able to enter into marriage (156/2015). Same-sex couples had been able to register their partnership in Finland as of 1 March 2002.
The amendment to the Marriage Act that entered into force on 1 March 2017 didn't change the classification of marital status.
For reasons of data protection, in municipal tables those living in a registered partnership are classified together with married persons, as are those divorced or widowed from a registered partnership with divorced and widowed persons.

The classification of marital status is as follows:

Marriage
Starting from the statistical reference year 2017, contracted marriages refer to marriages where at least one of the spouses has resided permanently in Finland on the day when the marriage was contracted. The amendment to the Marriage Act that entered into force on 1 March 2017 enabled same-sex couples to enter into marriage (156/2015).
The number of marriages contracted annually is, thus, the number of marriages entered into by same-sex and opposite-sex spouses.
In 1980 to 2016, contracted marriages referred to marriages of women living permanently in Finland unless otherwise stated.

Registered partnership
Registered partnership of two persons of the same sex aged 18 or over (Act on Registered Partnerships of 9 Nov. 2001/950). Partnership is registered by an authority entitled to perform civil marriage ceremonies. Registered partnership is dissolved when one partner dies or is declared dead, or when it is dissolved by court order.