New Zealand's population might have reached the 5 million milestone last year, but it wasn't because we're having more babies.
In fact, the country's fertility rate plummeted to its lowest-ever level in 2020, to just 1.61 babies per woman over their lifetimes.
"Fertility rates in New Zealand were relatively stable between 1980 and 2012, but have generally decreased since then," said population estimates and projections manager Hamish Slack.
"Since 2013, the number of women of reproductive age has increased by 11 percent and the number of births has decreased by 2 percent."
Sixty years ago, the average Kiwi woman had four babies. That fell to two in the mid-1980s, and aside from a brief blip in the early 2010s, has been falling ever since.
There were 57,753 live births here in 2020, down 2064 from 2019 - a drop of 3 percent.
Since 2012, our fertility rate has been below 2.1 - the level needed for a population to replace itself through natural reproduction. New Zealand's population has been growing consistently regardless thanks to immigration.
Many developed nations have fertility rates below replacement level, including the US, Australia, UK and Canada. Japan's is so low - 1.42 - that its population is falling, even with immigration.
By the regions
Northland and Gisborne had the highest fertility rates at 2.3. Mothers in those two regions were also the youngest - a median of 28.4 in Gisborne and 28.9 in Northland.
"If the median age is lower in a region, then on average, women from these regions are having children earlier in their reproductive lives," Statistics NZ said. "They therefore have the potential to have more children than women who start having children later in their reproductive lives."
The lowest rates were found in Otago and Wellington - 1.4 and 1.5 respectively. They also had the old median mothers at 31.4.
"Regions with large tertiary education providers, such as Otago and Wellington, have large numbers of young women who are within childbearing ages but generally not having births while studying," said Statistics NZ. "This often means that these regions are likely to have lower fertility rates than other regions."
Is COVID-19 to blame?
With the vast majority of 2020 babies having been conceived in 2019 and March 2020, the lockdown - which forced people to stay at home with children and flatmates, and cut socialising opportunities - can't be blamed for driving the fertility rate to a record low.
Statistics NZ says whether or not the six-week lockdown resulted in more or fewer babies will be revealed in the data set for release in May.
Something COVID-19 can be credited with, ironically, is the lowered death toll in 2020. Deaths were down 5 percent to 32,613, the biggest drop on record.
"Drops in the number of deaths happen from time to time, despite a growing and aging population," Statistics NZ reported. "However, the latest fall coincided with lockdown restrictions as a result of the COVID-19 pandemic. Alert level restrictions, including stay-at-home instructions, limits on road and air travel, and temporary business closures may have played a part in the reduced number of deaths."
The median age at death for a man was 78 and for a woman 83.
A newborn boy born in 2020 has a life expectancy of 80.3 years, and a girl, 83.9. For those who have just reached retirement age, men can expect to live another 19.6 years and women 20.9.
The infant mortality rate was four per 1000 live births - less than a quarter what it was in 1970.
