Last month, when releasing the census with great fanfare, Peter Costello once again took credit for the recent slight rise in the birth rate. For the record, Australia’s fertility rate increased to 1.81 births per woman in 2005, up from 1.77 the year before. The replacement rate (the average number of babies a woman needs to have in her lifetime to keep the population steady) is 2.05.
It’s seemed to me for a while that the steady decline that’s been happening in fertility rates is about far more than women having fewer babies. It’s also a major change in the life pattern of women as people and mothers.
Here’s the graph of fertility rate for the last eighty years. You can see that there is a lot of variation (source Australian Bureau of Statistics).
But here’s the rub. The fertility rate you see on this graph is the average rate of all women having babies at any given time. My (so far ancedotal) view has been that in the last 20 years, there has been a major shift in behaviour. Women are having more of their children in their 30s than their 20s. And as this shift in behaviour works its way through the age scales, there has been a lack of babies. The women born in the 50s finished their families in their early 30s, and the women born in the 60s waited out their 20s and started in their 30s. A gross generalisation, of course.
But the census prompted me to have a look at the statistics in more detail. So its possible to create the graph below, which is a projection of the lifetime births per woman by year of birth from the birth statistics. Its a projection for the last 10 years of the graph, but that doesn’t make a major difference to the overall picture (Source Australian Bureau of Statistics plus my own analysis).
While the rate of children per woman has been decreasing (from a peak of just over 3 for women born in the mid 30s) it is much smoother, and we’re still pretty close to the replacement rate for women like me (born in the late 60s).
So I don’t think Peter Costello’s Baby Bonus had much to do with fertility changes at all – it’s just that the women born in and around 1971 (the peak number of births in Australia’s history still) are getting to around the peak of their peak childbearing years – the mid 30s.