So, what, if you don't work you can't invest in property?
20 million potential investors is too high because that includes children who are unlikely to be investing in property. There are around 4.7 million children under the age of 18. Nett=15.3 million.
Married or de-facto couples are also less likely to invest independently in my view. 8.3 million people are married (1998 data) so collectively that might lose another 50% (4.15 million). Nett=11.15 million. (Or put another way, couples investing may possibly be investing through a trust as a singular entity).
So, roughly speaking we are talking about 10% of the likely candidates for having a rental property actually do have one.