I wasn't that close, I actually shared that image above on a forum and got told, no way would Australia be at almost 25% no-religion at the 2016 Census... yeah I was way under... glad I was.
Well I've done the graph again, saving my work this time. I averaged out the change over the last 10 census' (including the one where Christianity went up, and the one were no-religion went down and got the below... so this is pretty rough. Taking this as fact, Christianity will disappear between the 2111 and 2115 census. Of course it will be irrelevant to public policy long before then. It will be irrelevant as some economists put any idea at a rising tipping point or around 30%. 30% is when the idea (in this case non-religion) becomes popular enough to spend time addressing. 30% is when the rest of populace, politicians included need to start taking heed. Good luck, of course appealing to a bunch of non-religious, people who probably think at length on things that concern them, and likely have all different conclusions based on the data they have received.
Christianity will become a minority after 2041, this is pretty exciting as it is within my lifetime, hopefully no other magical or poor thinking takes its place of course.
I have lots of friends who have a much better grasp on statistics than I ever want to hold, so I am sorry that this has likely hurt your brain with its poor assumptions...
It is a fact that came out of this census, that us the non-religious outnumber the Catholics.
