Perth / Western Australia

and that an average household used 15-20 (per this chart)

Uhh, careful now. That's the average person. A household of 4 would multiply that number by 4!

Only, not really. It's difficult to try to make a comparison between the per capita emissions of a country and the direct emissions by an individual. Many of the biggest emissions will not be captured by an individual's footprint, even in a calculator attempting to capture as much as possible. It's why the entire notion of individuals' "carbon footprint" (a concept created specifically by BP as a way to shift blame onto individuals and stall real action on climate change) is mostly bs.

Also worth noting that this chart specifically says that land-use change is not considered. That's a big problem with agriculture, especially beef and dairy production. Aside from the ecological and other environmental issues it creates, it also releases a lot of carbon.