The nation's econocrats have been pondering the resources boom for years, but one thing they've been expecting isn't coming to pass: we're not getting huge deficits on the current account of the balance of payments.
Last week's figures showed a deficit of just $5.3 billion for the June quarter, about half what it was in the March quarter. This included a surplus on the balance of (international) trade in goods and services of
$7.5 billion - the fifth quarterly surplus in a row - offset by a deficit on net income payments (our payments of interest and dividends to foreigners less their payments to us) of $12.8 billion.
Switching to the year to June, the current account deficit was $33.6 billion, down from $53.3 billion the year before. Expressed as a proportion of gross domestic product, this was an amazingly low 2.4 per cent, down from 4.1 per cent the year before.
So why were the econocrats expecting bigger deficits? Because most of the money to finance the surge of investment in new mines and natural gas facilities would have to come from foreigners, thereby adding to the surplus on the capital account of the balance of payments which, with a floating currency, is always exactly balanced by a deficit on the current account.
And why haven't the big deficits come to pass? Because household saving has been a lot greater than the econocrats were expecting. The more the nation saves, the less it has to call on the savings of foreigners to finance its investment spending.
Last financial year's current account deficit is down because saving is up while the mining investment boom is only just getting started.
As that boom gets under way, the current account deficit is likely to grow. This year's budget forecast a deficit of 4 per cent of GDP for this financial year, rising to 5.25 per cent in 2012-13. Even so, those figures are smaller than the econocrats had been expecting before they realised how much more households were saving.
Last week's national accounts showed households saving a net (that is, after allowing for the year's depreciation in the value of household assets) 10.5 per cent of household disposable income. This is unlikely to be an aberration; it's more likely to be a reversion to our earlier thrifty habits.
If you're more used to thinking about the current account deficit in terms of exports and imports, I should explain that these days economists tend to look on the other side of the coin, which shows saving and investment.
The current account deficit equals the capital account surplus, which represents the net inflow of foreign financial capital to the Australian economy. As we've seen, we call on the savings of foreigners to finance that part of our investment in new physical capital than can't be financed by our own saving.
This net inflow of foreign financial capital allows us to import more goods and services than we export, including imports of capital equipment.
The net capital inflow also helps us finance our net payments of interest on the nation's net foreign debt and our net payments of dividends on net foreign equity investment in Australia's businesses - though the ultimate justification for our foreign borrowing is the profits we make from our physical investments.
The nation's annual investment spending includes not just business investment in equipment and structures, but also public investment in infrastructure and households' investment in the construction of new homes.
Similarly, the nation's annual saving includes not just the amount saved by households, but also the saving companies do when they retain part of their after-tax profits rather than paying them all out in dividends and the saving governments do when they raise more in revenue than they need to cover their recurrent spending.
According to an article in the federal Treasury's latest Economic Roundup, in the decade or so before the first stage of the mining boom began in 2003, the current account averaged 3.7 per cent of GDP. During the first stage it averaged 5.7 per cent, but since the global financial crisis it's averaged 3.3 per cent.
Before the mining boom, gross national investment spending (that is, before allowing for the annual depreciation of assets) averaged 24.3 per cent of GDP. Since the start of the mining boom it's averaged 27.9 per cent.
Had the level of gross national saving stayed unchanged, that would have increased the average current account deficit by 3.6 percentage points. In fact, national saving has increased from 22.2 per cent to 24.5 per cent.
While households have been saving a lot more in the period since the global financial crisis, federal and state governments have fallen into operating deficit, meaning they've gone from saving to dissaving. As they get their budgets back to operating surplus in the next year or two they'll be adding to rather than subtracting from national saving.
Company profits have been high in recent years and many companies have been saving a fair bit. Mining companies, in particular, have been reinvesting a lot of their after-tax profits in expanding their activities. (To the extent that those retained earnings are owned by foreign shareholders, and were initially counted in the balance of payments as capital outflows, their reinvestment is counted as foreign capital inflow, even though the actual dollars never left the country.)
Australia's persistent current account deficit has always reflected a high rate of national investment rather than a low rate of national saving. Although our household saving rate was quite low during the decade or so to the mid-noughties, our overall, national rate of saving has been around the average for the developed economies.
Point is, should our current account get a lot bigger in the next few years, it will be because the mining construction boom involves a lot more investment spending, not because we're saving less.
We've done much hand-wringing lately about ''the cautious consumer'' (especially when we imagined consumer spending was weak, which we learnt last week it isn't), but the fact that increased household saving has stopped the strong growth in household income translating into booming consumer spending has some big advantages.
If we can avoid a consumption boom occurring at the same time as an investment boom, the Reserve Bank won't need to increase interest rates as much to control inflation and this, in turn, will avoid adding upward pressure to the Aussie dollar.
