It's drawn little comment, but the decades-long drift of students from government to non-government schools has ended.
Figures released by the Bureau of Statistics last month show that 65 per cent of our 3.8 million students went to public schools in 2016, the same proportion as in 2013. If anything, the public-school share is creeping up.
The non-government share divides between Catholic systemic schools with 20 per cent and independent schools with less than 15 per cent. I'll refer to both as private schools.
But the public schools' 65 per cent today is down from 79 per cent in 1977.
Let's start by trying to explain those many years of drift before we wonder about why it's stopped.
When Ipsos Public Affairs asked people why they thought other people sent their kids to private schools, the most commonly cited reasons included the higher standard of education (50 per cent), the better discipline (49 per cent), the better facilities (46 per cent), the size of classes (43 per cent) and because it's a status symbol (40 per cent).
Almost uniquely among other developed countries, Australian parents have a much higher proportion of private schools to choose, and have been given greater freedom to choose between government schools.
Successive federal and state governments have seen greater parental choice between public and private as a virtue, and have encouraged it by increasing their combined grants to private schools at a much faster rate than their funding of public schools.
But I have my own theory on why so many people have opted for private schooling. I think a lot of it gets down to parental guilt.
These days families have much fewer children, which means parents take a lot more active interest in their kids' schooling than they did when I was the last of four.
And these days both parents are more likely be in paid work – meaning they have more money to spend, but see less of their kids than their parents did.
So what more natural than for parents to believe that, in their decisions about how to spend their income, ensuring their kids get the best education possible should have high priority.
And what's more natural in our market economy than to assume that the more you have to pay for something, the higher quality it's likely to be.
It's the old male cop-out, spread to women: I may not see as much of my kids as I'd like to, but I'm working night and day so I can afford to give them the best of everything.
The more materialist you are, the more you're inclined to judge a school by the quality of its facilities – gyms and swimming pools, music, art and drama theatres – than by the quality of its teachers.
Of course, the former is, as economists say, much more "observable" than the latter.
But whatever people give as their reasons for preferring private schools, you'll never convince me they're not well aware of the status they gain by sending their kids to private schools, especially independent schools.
Private schools are among the things economists classify as "positional goods" – they reveal your position in the pecking order.
But what's changed? Why has the drift to private schools come to an end?
One possibility is that the slow wage growth of recent years has made it harder for parents to afford private school fees.
This may be particularly the case for independent schools, where the rate of increase in fees from year to year bears little relationship to rate at which teachers' salaries are rising.
Nor does the rate at which government grants have been growing seem to have had much effect in slowing the rate at which independent school fees have grown. (The extra government grants may have gone into improving schools' facilities.)
My guess is that, as economic textbooks predict, independent school fees rise according to what the market will bear. They judge how strongly demand for their product is growing relative to supply by the length of their waiting lists.
In any case, keeping the cost of independent schooling high is an essential element in maintaining its status as a positional good.
Another possible contributor to the end of the drift to private schools is the decision of state governments – particularly NSW governments – to increase the number of places at selective schools. Why pay fees when you can get what you want inside the government system?
As a parent who's had one of each – independent and selective – I can assure you selective schooling works well as an (intellectual) positional good.
But there's one last possible contributor to the end of the trend to private schools: maybe parents are realising that paying all those fees doesn't buy your kid superior academic results along with their old school tie.
Julia Gillard's My School website has done little to encourage greater competition between schools (a silly idea she got from economists), but it has provided a fabulous database for education researchers.
Various researchers have used it to demonstrate that the best predictor of children's academic results is the socio-economic status (including level of educational attainment) of their parents.
And when you take account of parents' socio-economic status, there's little evidence that kids of similar backgrounds do any better academically at one kind of school than another.
Ross Gittins is the Sydney Morning Herald's economic editor.