The numbers have been released by the Comptroller, New York City's chief financial officer, which said that there are 83,000 fewer jobs in the city than at this time last year.

Time and time again New York City has overcome great difficulties... I know that we will meet this challenge, and emerge stronger than ever

William Thompson New York City Comptroller

Whether the final cost rises as high as $95bn - the low-end estimate is $83bn - will depend largely on how many of those jobs are permanently shifted out of the city, said the Comptroller, William Thompson.

The city had been suffering from a mild downturn before the twin towers were hit by hijacked jetliners, collapsing both and killing thousands.

But the tragedy and its aftermath made things worse, snuffing out a nascent recovery which could have created 60,000 new posts and destroying property which - the Comptroller estimates - will cost $21.8bn to replace.

Added to which, many of the victims of the disaster were well-paid financial operators. Given an average $130,000 annual salary, the city estimates, their lifetime earnings would have contributed $8.7bn to the city's economy.

Aid but not enough

In the wake of the disaster, New York had an unemployment rate of 7.7% in July, up from 5.8% at the same time last year and well above the national average of 5.9%.

Part of the job losses have come from firms - including the high-profile financial firms which were forced to scramble for space in New Jersey, across the Hudson River - which have yet to return.

About 13 million square feet of office space - enough to fill the business district of Atlanta or Miami - was wiped out.

The federal government has come through with promises of aid totalling $21.4bn, of which $2.7bn has thus far arrived.

But that will not spark an economic rebound, Mr Thompson told reporters, not least because much of it is due in tax breaks and debt refinancing.

"Time and time again New York City has overcome great difficulties," he said.

"I know that we will meet this challenge, and emerge stronger than ever."

Nearly $3bn has been lost in taxes too, he said, while $500m needs to be paid in overtime for workers cleaning up Ground Zero - an expense Washington will not underwrite.