Today
How has the share of children born outside of marriage changed?
The Organisation for Economic Co-operation and Development (OECD), a group of 38 mostly high-income countries, brings together data on family life and family policy in its Family Database, which covers its members, EU countries, and some partner countries.
One of its indicators is the share of children born outside of marriage, meaning births where the mother was not legally married at the time. The OECD collects these figures from national statistical offices and Eurostat.
In 1970, fewer than one in ten children were born outside of marriage in 20 of the 25 countries with data for that year and 2023. The share has risen in all 25 since then — in Spain, it went from 1.4% to 50%.
Most countries don’t have long-term figures on how many couples live together unmarried, which makes this indicator one of the few ways to follow that change over decades.
I recently updated the chart with the OECD’s release from October 2025. For most countries, the data used to end in 2020 and now goes to 2023, and to 2024 for five of them. Colombia is in the data for the first time, from 1998 onward, and has the highest share of all. In 2023, 87% of births there were to mothers who weren’t married.