Marriage – how often, when, how long

I read a fascinating article from the truly brilliant American National Public Radio on marriage between people of different ethnicities. It charts the change in societal attitudes towards inter-ethnic marriage: in 1968 only 20 percent of Americans thought it was okay for a white person to marry a black person. Fast-forward to 2011: 96 percent of African-Americans and 84 percent of whites Americans accept the idea, although inter-ethnic marriages are still rare – only 7.4% of marriages in the US are between two people of different ethnicities.*

This triggered my interest in marriage in general, especially because I thought that marriage was becoming increasingly popular – certainly everyone that I know seems very keen on it these days. And everyone loves a good wedding. Such a spirit of optimism, enthusiasm and hope.

Sadly New Zealand does not seem to have publicly available statistics on marriages by ethnicity. Although I have some other information on ethnicity sent by someone helpful at Stats NZ, so I might pen another post on that.

But we do know quite a lot about marriage from Stats NZ data, including how many people get married or civil unionised. The rate of marriage (adjusted for the size and age of the population) is gently falling over time, although the number of marriages is pretty static at around 21,000 a year. Men are slightly more likely to re-marry than women following divorce, and women are very slightly more likely to remarry after the death of a previous marriage partner (presumably this is related to the fact that women are lucky enough to live longer on average).

Not such good odds

For the year to December 2010, your odds of getting married were about 1 in 80, down from 1 in 22 in 1971 (the most popular year for marriage since records began in 1961).

Proportion of marriable people who got married by year**

Civil unions became possible on April 26 2005. (Good on those of you who were first in the door to tie the knot on April 29). There have been 2,200 registered since then (compared with nearly 130,000 marriages), and about 80% of them were same-sex civil unions.

Not so young

The median age for marriage has continued to go up reaching 30 for men and 28 for women first marrying in 2010. The median age for marriage overall (including second and subsequent marriages) is now 32 for men and 30 for women.

Stats presents another way of looking at it:

In 1971, 62 percent of men and 52 percent of women marrying for the first time were aged 20–24 years, compared with 15 percent and 22 percent for men and women, respectively, in 2010. Teenagers comprised 36 percent of women who married for the first time in 1971, but only 3 percent in 2010.

Below is the 2010 age distribution of marriage (this is for all marriage – not just first ones). You can see 30% of women and 27% of men who get married do so between the ages of 25 and 29.

Age distribution of marriages in 2010

Not all sunshine and lollipops

So basically marriage is getting less popular, and it is happening later in life. The reason I thought the opposite (given the behaviour of people around me) must be because I am of an age when people who are going to get married do so (although my friends have generally been at the older end of the scale – sigh), and I am yet too young to see many divorces (long may it continue).

Speaking of divorce, this is the trend in the number of divorces over time. I have put it on the same chart as marriages so you can see how many more marriages there are than divorces. On average over the past 20 years we have added ten thousand to our stock of marriages every year – with about twenty thousand marriages and about ten thousand divorces.

You can see that divorce numbers grew after the law changed in 1981 to allow no-fault dissolution of marriage after two years living apart, but the divorce numbers have recently fallen away a bit. Note that the number of divorces and marriages in any year are only indirectly linked. The number of divorces this year depends on the divorce rate and the number of married people, and therefore the number of marriages in the past, not the number in the current year.

Number of divorces and marriages over time

Divorce has become a bit less popular recently. Around 1.2% of existing marriages ended in divorce each year from 1985 until 2006. Since then though, the divorce rate has settled down to a more modest 1%. About 40% of divorces involve people with children aged under 17 – down from more like 50% twenty years ago.

So if 2012 is just like 2010, if you aren’t married, you have a 1 in 80 chance of getting married. And if you are already married, you have a one in a hundred chance of divorcing in the coming year.

Til death us do part

In line with the declining popularity of divorce, marriages are growing in length. Stats NZ says that about a third of marriages from 1985 had ended within 25 years, which is a glass-half-empty way of saying that two thirds of marriages last more than 25 years. I suspect the length of marriages is growing over time; partly as an effect of the falling divorce rate, but also because athough people are marrying later they are also living longer, implying longer marriages for those who stay together. Almost half of divorces take place after between 5 and 14 years of marriage. One in eight divorces is for couples together for less than five years.

Median length of marriage for those than end in divorce

Like rain on your wedding day

Stats also collect data on which month people choose for their nuptials. Unsurprisingly, people like to get married in January, February or March – 40% of weddings take place in the summer, compared with 14% in the winter. Ten years ago, it seems October and November were rather more popular than they are today. If we line this up with the number of rain days in each month (based on long-term average stats from NIWA), you can see why summer is so popular (the red line shows the number of rain days, the blue bar the proportion of weddings). Sadly there are no statistics on the impact of a sunny wedding on the likelihood of breakup in the future.

If you really want sunshine on the special day, Scott Base in Antarctica seems to be the sunniest place in New Zealand. It had an average of a remarkable 380 hours of sunshine in January when the sun never sets (data from 1957-1959). Although the cold might impose some restraints on the wedding dress, penguin would make an interesting feast. By comparison, sunny Nelson only gets 266 hours of sunshine in January – using data for the thirty years to 2000.***

Marriages and rain days by month

PS Unsurprisingly, I guess, the age of mothers having children has gone up as well as the age of marriage. Below shows the distribution of live births by age of the mother in 1961 and 2010. In 1961 more than a third of children were born to mothers between the ages of 20 and 24. Today that can be said only of 18% of children. The most popular age is 30 to 34 (28% of children born in 2010 had mothers this age), followed by 25 to 29 (close behind at 25%).

Age of mother at birth

* Presumably there is a higher rate of inter-ethnicity amongst new marriages but I don’t have a number for it.

** These figures are what Stats NZ call the “General” marriage rate – the number of marriages + civil unions per 1,000 estimated not-married people aged over 16. (There does not seem to be an upper age limit). I have converted it to a percentage to make it a bit easier to understand.

*** Weather data comes from NIWA