The International Monetary Fund in its Fiscal Monitor report last month puts a net present value on the increases in pension spending by the Governments of advanced economies between now and 2050.
In New Zealand's case it is the equivalent of 66 per cent of gross domestic product or $140 billion in today's dollars.
And that is just the increase, not the entire cost of Super.
It is more than twice the average of 31 per cent of GDP for advanced economies.
It means that by 2030 the share of GDP going to fund superannuation will increase by 2.3 percentage points, the IMF reckons, twice the average pension-related increase in the fiscal burden for advanced economies.
Meanwhile the Organisation for Economic Co-operation and Development has calculated the "fiscal gap" for New Zealand and 25 other developed countries.
The fiscal gap is the immediate and permanent rise in the primary balance (that is before debt servicing costs) needed to achieve sustainable levels of gross government debt, which the OECD defines as 50 per cent of GDP by 2050.
The OECD economists calculate that our fiscal gap is just under 10 per cent of GDP.
Gulp.
That makes it the second highest, after Japan's, and slightly higher than that of the United States - two countries that are hardly the poster children for fiscal providence.
New Zealand starts with the fifth lowest level of gross debt, relative to GDP, in the OECD, but on the other hand the deterioration in the fiscal bottom line was among the highest.
The impact of the global financial crisis has been substantial, the OECD economists say, but it often represents a relatively small part of the overall fiscal challenge, which for many countries is driven by future pension and health care spending pressures.
Superannuation is a particularly large fiscal problem in New Zealand because the way we fund retirement income is unusually heavily reliant on a taxpayer-funded pay-as-you-go pension.
It is one of only four countries with a flat-rate universal pension, where everyone gets the same amount. The others are Canada, Denmark and Russia.
There is no income or asset test, though it is taxed with all other income.
It is unrelated to past earnings, paid to all residents (subject to a relatively short residency test) once they turn 65 and indexed so that it delivers a third of the average wage per superannuitant.
In the current fiscal year it will cost $9.6 billion or 4.6 per cent of GDP.
But as the population ages, the Treasury estimates the cost will climb, reaching 8 per cent of GDP by 2050.
It has been that high before, but not for long. The cost was considered insupportable.
Back in the late 1970s Robert Muldoon lowered the age of eligibility from 65 to 60 and raised the payment from 65 per cent of the average wage (for a couple) to 80 per cent.
That drove the cost up to around 8 per cent of GDP and was reversed in the 1990s, which pulled the cost back down towards 4 per cent of GDP.
Even so, superannuation represents a quarter of the Crown's core operating expenditure, and the babyboomer generation has only just started to retire.
All of this has two main implications for policy here and now.
One is that it strengthens the case for returning to Budget surplus as soon as possible - a surplus large enough to resume contributions to the Cullen Fund and at a higher rate, to make up for the time and money lost since contributions were suspended when deficits returned in the wake of the GFC.
There are other factors, cyclical ones, which argue the other way, for not being so hell-bent on returning to surplus. But that's another story.
The other main implication of the long-term fiscal threat from our current superannuation regime is that it is craven irresponsibility for the Government to refuse to even talk about changing the entitlement parameters.
It is a given that any such changes need to be flagged well in advance so that people can adjust their finances accordingly.
The longer the Government pretends there is no problem, the more abrupt, disruptive and unfair those changes will be when inevitably they come.
Shearer in a speech last week dropped the policy Labour had taken into the election of resuming contributions to the Cullen Fund immediately.
"New Zealanders saw this as borrowing to invest and they didn't like that."
He also admitted that "we didn't signal our intentions very well in this area, to raise the age [of eligibility] to 67".
A third of the 27 economies the IMF ranks as advanced are raising the age of entitlement, including Australia, the United Kingdom and the United States.
Unfortunately so much time has already been lost that, because of the need to give people decent notice, the age would not start rising under Labour's policy until 2020 and by the time it reached 67, 12 years later, the average life expectancy for those attaining that age would be about two years longer anyway.
It only nibbles at the problem.
"We don't want to end up with a government forced to choose between young and old," Shearer said.
He might have added that the young are free to pre-empt that choice by taking themselves off to Australia or farther afield.
If the risk of swelling the Kiwi diaspora is an argument for cutting tax rates or maintaining concessionary student loans, it is certainly also an argument for putting superannuation on a sustainable fiscal footing.
"We are willing to discuss this openly and across all political parties," Shearer said, "because it is such a tough decision and deserves the widest consensus".
But for the Prime Minister it is "not a priority".
Unless he has some means of changing the laws of arithmetic or the passage of time, it ought to be.
