Part of the reason for that could be that New Zealanders were marrying much later in life.
In 2020, the median age at first marriage or civil union was 29.5 years for women and 30.6 years for men. In 1971 it was 20.8 and 23.
The median age - of all marriages rather than just first marriages - of males getting hitched was 32.4 years and 30.8 years for females last year.
Only 1248 marriages and civil unions were registered to overseas residents last year, down from 2892 in 2019.
"Border restrictions due to the Covid pandemic impacted this, as 90 per cent of these marriages and civil unions were registered before the end of March 2020," a statement released by Stats NZ said.
By contrast, divorce rates were also down - for every thousand existing marriages and civil unions there were 7.6 divorces. This was compared to 10.1 in 2010.
The number of children under the age 17 years whose parents were granted a divorce last year was 5973, compared to 6732 in 2010 and 8775 in 2000.