The day Australia’s voluminous Census data is released is like Christmas for economists, demographers, policymakers and social researchers. It’s even better, in fact, because this particular day of enlightenment comes only every five years! Indeed, like clockwork since the first Census in 1911, the official statistician has released this invaluable snapshot of our nation.

Within the countless piles of detailed and diverse information, nerds like this humble correspondent find priceless gems where cynics otherwise may see only rocks. The data provides important, invaluable insights into long-term changes in our economy, ourselves and our lifestyles that can have profound implications for policy. So much so, in fact, that without the Census data, policymakers effectively would be poking around in the dark.

Unfortunately, this time around, collection of the Census last August was caught up in controversies about privacy and, more profoundly, the disruption to the Census website on the very night millions of Australians were trying to complete it. There was talk that the results would be irreparably compromised and even hysterical speculation that the regular collection of the Census data should be suspended indefinitely.

The collection troubles did attract headlines for weeks, but turned out to have only a minimal impact on the quality of the data. Indeed, an independent analysis commissioned by the Australian Bureau of Statistics (ABS) found despite the interruption on Census night and the extended downtime, the response rate was equal to that of the 2011 Census. Also, importantly, there was no discernible deterioration in the accuracy or statistical validity of the data.

So, what can we learn from this latest snapshot of our nation? The headline grabbers were that our population is, on average, older than ever and that a greater proportion of us was born overseas (26 per cent). The results also suggest we are less religious than before, although critics claim this reflects a change in the way the question was asked rather than increased secularisation. Women (51 per cent) continue to outnumber men.

Our population is approaching 24 million, a near nine per cent rise since the last Census and more than a doubling since 1966. As before, most of us are city-based, with two-thirds of Australians living in the capital cities. In fact, population growth in the capitals is twice that for the rest of the country, adding to the growing pains of the major centres. Melbourne, often judged among the world’s most liveable cities, is growing faster than Sydney in absolute terms.

For economists, there are many invaluable nuggets of information that provide crucial insights on issues like demand for housing and government services. The information related to housing, in particular, helps us understand why house prices have been rising so quickly, and the lasting consequences of deteriorating housing affordability.

For example, although there were 10 million dwellings in Australia last year, a stunning 11 per cent of them were unoccupied on Census night. This reflects temporary absences at the time, but extended vacancies are almost certainly a contributor to shortages of housing in key markets. Many investors choose to leave their properties vacant, relying on capital growth for returns, which has been a pretty good bet in recent years. The growing number of vacant properties, in fact, prompted some state governments to impose vacant-property taxes in their latest budgets.

The average number of people per household slipped to 2.6 in 2016, down from 2.8 in the 1991 Census. This apparently small change over a generation may seem like a rounding error, but it has profound implications on national demand for housing. Indeed, one in four households now comprise just one person, up from one in five in 1991. The increase in single-person households is a counterbalance to more young people living at home with their parents. Unsurprisingly, the share of higher density dwellings rose to 26 per cent.

Another telling statistic from the Census was that home ownership slipped as the share of rental dwellings rose. Only 31 per cent of houses were owned without a mortgage last year, down from more than 41 per cent in 1991. Another 35 per cent of houses were “owned” with a mortgage in 2016 – 31 per cent were rented, up from 27 per cent a generation ago.