The person who posted this item on Rorate caeli used the term 'The Australian Catholic collapse', but from the graph above, the more appropriate term is 'decline' not 'collapse'(which would have seen the Catholic line plunge down to near-zero.).
Australia's declining number of Catholics:
A 'Francis effect'?
A sharp decline appears to come during the latter half of the 2006-2016 decade (2011-2016, if the graph is drawn to scale), practically entirely inside the Pope Francis period.
[Last two years of B16 and first 3 years of JMB, to be more exact].
During this time, the Church had a similar decline to all other Christian communities in Australia. But perhaps the most concerning data from the graph is that those who profess 'no religion' are now the largest 'faith' group in the Australian population.
The graphic clearly shows a degree of Catholic stability, with a gentle decline in the second part of the Wojtyła years and during the Ratzinger pontificate, followed by a strong decline in the Bergoglio period, as the Church finally follows the same path of the Protestants.
And, indeed, why should any unsure Catholic, baffled as well by the abuse crisis, remain a Catholic when the signs from Rome seem to indicate that being a Catholic is completely dispensable?
A propos, one might have expected a blockbuster book by now on 'The Francis effect' if the initial anecdotal enthusiasms in 2013 about a 'significant shot in the arm for Catholicism' had translated to actual positive data, instead of which the data all show negative trends for any important parameter of Catholic life since Bergoglio became pope... Indeed, it's hard to see how more people might become Catholic under a pope for whom Catholicism is just one 'religion' among many, and whose real interest is to impose Bergoglianism in its place, and not just as a dominant world religion but as 'the' prototype and model for the 'one world religion' that Hans Kueng had hoped to be his legacy! (Sorry, Hansie, you have to be pope to impose your will as Bergoglio does now.)