When did you last see a $100 bill?

The denomination makes up about 20 per cent of notes issued annually, but you can go years and not see one. Now the puzzle of who has our cash is translating to all denominations. The amount of money printed annually has not changed for years but cash use is falling.

Cash under the bed: One theory about the lack of $100 notes in circulation is that people are simply stashing it somewhere. Credit:Bloomberg

The Reserve Bank of Australia has conducted surveys of what payment options people use every three years since 2007. The latest, of around 1500 people who recorded how they paid for things over two weeks late last year, found that cash was used for 47 per cent of transactions in 2013, down from 62 per cent in 2010 and 69 per cent in 2007. Card use rose to 43 per cent from 31 per cent in 2010 and 26 per cent in 2007.

But the total amount of cash issued by the RBA has stayed rock steady as a proportion of GDP for years – in fact it has grown without adjusting for economic expansion.