In the 2007 Federal Elections, 7.8% of Australia's population voted Green.
In the seat of Bass it was 15.3%
In the seat of Braddon it was 8.1%
In the seat of Denison it was 18.6%
In the seat of Franklin it was 14.4%
In the seat of Lyons it was 11.2%
Total first preference votes from Tasmania: 334,938
Total Green votes from Tasmania: 43,893
% of Tasmanians who voted Green: 13.1%
That's almost twice the national average. In other words, if you live in Tasmania, you are almost twice as likely to vote for the Greens as anywhere else in Australia.
This is not surprising since, in 1972, the United Tasmania Group formed, which was the first Green political party in the world. One of the leaders of the UTG was Bob Brown, who is now the leader of the Australian Greens.
Two mainland lower house seats had greater Green votes than Denison: Melbourne (22.8%) and Sydney (20.7%). Craig Schwarze lives in the Sydney seat, which is ironic considering his environmental stance (or maybe it's appropriate!). The Queensland seat of Flynn is the least "Green" of all lower house seats, gaining a mere 2.0% of the primary vote.
It was the Victorian seat of Melbourne (which I mentioned above) which nearly resulted in the Greens getting more votes than the Liberal party (19,967 vs 20,578). Had the Greens gotten more votes it would have resulted in a run-off between the ALP candidate and the Greens candidate (which would've been won by the ALP for sure). I am reasonably certain that by the next federal election, at least 3 lower house seats will involve the Greens as part of the 2-party run-off (but probably not win any of them).