Sydney is bleeding 22,000 citizens a year to all parts of Australia, and for the first time the people deficit covers all key groups, from students and young singles to families and retirees.
The nation's biggest city is the only capital to lose more people aged 15-34 than it gained from interstate migration between 2001 and last year, and is the only capital apart from Adelaide to go backwards for both professional and blue-collar workers.
But for every Sydneysider who is forced out by the cost of living, another two are replacing them from the overseas migration program.
New official data analysed by The Australian reveals a dramatic realignment in the nation's make-up as young and old alike criss-cross the continent from Perth to Melbourne and from Sydney to the "rest of" Queensland - everywhere outside the capital city.
Hobart is the surprise packet, rising to third place behind Brisbane and Perth as the most popular city destination for interstate migrants, while the rest of Tasmania has leapt to second behind the rest of Queensland on the regional growth ladder.
The rest of Victoria and the rest of NSW are also in the black - breaking the past pattern in which they gave up more people to Queensland than they received in seachange and treechange retirees from Melbourne and Sydney.
The bigger picture shows that the rest of Queensland has replaced the state's capital as the nation's top people magnet, gaining 14,000 people a year compared with Brisbane's 10,000 a year.
The customised tables were extracted from the 2006 census, and track interstate migration over the past five years by age and qualification.
Responding to The Australian's analysis, demographic experts said the cause of the drift away from Sydney could be explained in part by its high property prices but also by its slowing economy.
The director of Monash University's Centre for Population and Urban Research, Bob Birrell, said Sydney's population decline mirrored the decline of its economy relative to the rest of Australia.
"We're seeing a big change in Sydney's relative attraction since 2001 or, really, since the Olympics. Sydney's demographic fortunes have changed sharply," he said.
"It's a chicken-and-egg thing, but the actual fact is that job growth in Sydney has slowed relative to Brisbane and Melbourne since 2001."
Demographer Bernard Salt said Sydney had become a divided city, between those who lived the "globalised" lifestyle, close to the CBD, and those who lived in the outer suburbs and rarely saw the Sydney Harbour Bridge.
"We've got floods of people coming in through the front door, into Sydney through Mascot (airport from other countries), but the backdoor's wide open, and Gen Y and down-shifters are streaming out. You don't find that to the same extent in other capital cities," Mr Salt said.
The latest census shows 111,400 more people left Sydney than arrived from elsewhere in Australia between 2001 and last year. This is almost double the rate of defection between 1996 and 2001, when 59,700 people left Sydney in net terms. Every capital, state and territory is officially an importer of Sydneysiders, the data confirms. Four out five Sydney defectors moved to the rest of NSW (46,500), the rest of Queensland (27,800) or Brisbane (18,700).
But Sydney's loss is most acute in the youth belt, which is the group providing the best gauge of a city's health. Almost one in 10 departing Sydneysiders was aged 15-34 - 10,000 out of the total 111,400. Sydney had previously been a net importer of youth, with 14,000 recruits from the rest of the nation between 1996 and 2001. The reversal over the past five years suggests cost of living pressures are pushing out Sydney's young and discouraging others from settling in their place.
The top beneficiaries of Sydney's youth drain were the rest of Queensland (5900), Brisbane (4600) and Melbourne (1800).
Sydney has struggled to meet the infrastructure needs of its population, but growing cities such as Brisbane could face the same pressures.
The other telling deficit for Sydney involves its local workforce. Sydney lost 7200 professionals and 5100 labourers between 2001 and last year.
Sydney also suffered professional worker deficits with Melbourne and Canberra (600 each).
Traditionally, Sydney and Melbourne received more professionals from Brisbane than went the other way. But the tables flipped in the past five years, although Melbourne lost 400 professionals to Brisbane, compared with 1700 who moved north from Sydney.
Simon Turner email@example.com