Relatively few $100 polymer Australian banknotes have been returned to the RBA for processing, the central bank admits in its Bulletin for September 2019.
$100 banknotes have been excluded from analysis of estimated banknote life, as "their expected life-span far exceeds the available data."
$36.8 billion in $100 notes are in nominal circulation, 45.5 per cent of the total stock by value.
The average life of old-series polymer banknotes increases as the denomination gets higher, RBA analyst Shane Aves found.
The life expectancies are:
• a little over 5 years for the $5 and $10;
• a little over 10 years for the $20; and
• around 15 years for the $50.
This, Aves notes "is consistent with lower-denomination banknotes incurring higher wear through greater use for transactions".