But figures released by the Australian Bureau of Statistics during the week may give pause to the mutual backslapping and champagne-cork popping. The worrying news is that the city's population is going backwards, despite its new-found confidence and popularity.

The city lost 1244 net residents in 2013-14, compared to net growth seven years earlier of nearly 2500.

Fluctuations are normal for a population of Canberra's size, and can be partly explained by factors like cuts to the public service workforce.

But drilling into the ABS numbers reveals a deeper problem – the type of people leaving are those we can least afford to lose, taxpayers aged between 25-64 who make up the largest group of departures.

The implications are clear. Unless those residents in the prime of their working lives can be replaced or coaxed into staying, there will be a hit to the ACT's revenue at a time when it is facing big bills for projects such as light rail, the Mr Fluffy buybacks and the city to the lake development.

If the population is at best stagnating, it raised the question, who is going to buy and move into the multitude of new housing and apartment developments already underway or in planning?

The city is still overly dependent on land tax to pay for essential services, but appears to be in denial about a fundamental problem – soon there may be more dwellings than people to live in them. Many of the major developments are also contingent on significant land sales to pay for them. But building too much too fast risks creating a crash in the property market. There are already signs this may be about to happen.

With the figures also showing a migration from Tuggeranong to Gungahlin, perhaps it is time to shift the focus from the inner areas of the city that have enjoyed the greatest resurgence to the south, the region that has suffered some of the greatest population losses over the past decade.

Following its initial boom Tuggeranong has for many years struggled to grow and offer enough employment for its residents. If they are now turning their backs on the area in favour of Gungahlin, as the figures suggest, it is a worrying trend that needs to be understood and addressed. Against this backdrop calls to expand Tuggeranong west of the Murrumbidgee river would seem premature.

Further, if areas outside the ACT's borders like Queanbeyan and Yass are continuing to grow, it may suggest that the housing affordability gap is forcing people who want to stay out of the city. With few other strings to its bow, Canberra's economy is heavily dependent on its knowledge economy to maintain is enviable status as an affluent, livable community. If those smart, young workers are now finding the city too expensive or not as attractive as first thought, it shows we can ill afford to be complacent.