Information for you:

Using unweighted data, the Australian Survey of Social Attitudes 2005
estimates that 1.3 per cent of women and 1.1 per cent of men are in
same-sex relationships.

A note on unweighted data and these results:

Weighting for the characteristics of the population is unlikely to
changes these figures much. AuSSA 2005 data over-represents formally
educated citizens, who are more likely to declare their same-sex
status, but under-represents younger Australians, who are also more
likely to declare their relationships.

I can say with some confidence that the current Census results
under-estimate the incidence of same-sex relationships in Australia.