The Australian Bureau of Statistics has released interesting research about same sex couples.
Here are some extracts:
The number of people living in a same-sex couple relationship has ... increased over the past decade. In 1996, 0.2% of all adults said they were living with a same-sex partner. By 2006, this had increased to 0.4% (to around 50,000 people). However, these figures may be an undercount of the true number of people living in same-sex relationships. Some people may be reluctant to identify as being in a same-sex relationship, while others may not have identified because they didn't know that same-sex relationships would be counted in the census....
In same-sex relationships, the average age difference (between partners) was 1.5 years
Changes in social attitudes in recent decades have led to greater acceptance of couple relationships outside of registered marriage, such as de facto and same-sex relationships. At the same time, broader social, economic and educational opportunities have become more accessible to most people (particularly women), which has made remaining single a more viable option.