Superannuation isn't just good for your personal retirement wellbeing; it's also good for the economy as a whole. Way back when former prime minister Paul Keating was introducing the superannuation guarantee in 1992, he envisaged a system that would also be able to support the economy through the provision of a pool of money that could be used, via the investment decisions of super funds and funds managers, for "nation building".

Superannuation is forced saving in every sense of the word. You don't have a say in it and your employer has to pay it by law. You could argue that your take-home salary, and perhaps the amount you can put aside for other types of investment, is smaller as a result but a bigger bottom line at retirement should be enough compensation.

But that's not the only benefit. There is also a big picture outcome as well. The impact this form of forced savings has on the economy could mean we're all better off by as much as $928 per head in economic growth.

How? We've already established that superannuation is forced savings. It turns out that that alone could have increased our level of national savings by between 1.5 per cent to 2 per cent of gross domestic product (GDP).

More than 80 per cent of superannuation money is invested locally and Allen Consulting, in a report prepared for the Association of Superannuation Funds of Australia (ASFA), estimates investment via superannuation funds added an additional $14 billion, or 4.5 per cent, to overall investment of $312 billion in the last financial year.

What's that got to do with anything? Stick with me because there are a few more numbers in this yet.

Because of that investment, capital stocks have grown much faster since 1991 when compulsory superannuation was introduced. Increased capital stocks have boosted GDP by an estimated 1.8 per cent or $20 billion – and that becomes our $928 per head or $2400 per household bonus.

See the graph for the projected impact on GDP of super for the next 10 years. Without superannuation, GDP in 2020 would be just $1.626 trillion or 3.2 per cent less than an estimated $1.679 trillion with it.

Some of the 80 per cent of superannuation monies invested locally is invested in our sharemarket. According to Allen Consulting estimates, that has about 23 per cent of the Australian share market held by superannuation funds. With a domestic market capitalisation of $1.09 trillion at June 30, that works out at $250.7 billion. It doesn't mean that without super funds the market would be that much smaller – but there's a fair chance if it was left up to us, we'd be spending these monies on consumer goods rather than saving for our 70s (and 80s and 90s).

In the shorter term, superannuation funds could provide some support for the current rally. Average cash allocations in funds' balanced options increased by nearly 2 per cent over the past two years as funds moved out of volatile shares. Cash allocations were 4.67 per cent in the third quarter of 2007 but sitting at 6.37 per cent at the end of last financial year.

Now things are looking up, funds are probably going to move closer to 2007 levels, which means there's a fair amount of cash sitting on the sidelines waiting to be reinvested. More than $11.7 billion in fact – and enough, perhaps, to provide the market with a very merry Christmas.