I found this very useful document that provides a quarterly Sensis® Business Index is an ongoing series of surveys tracking the confidence and behaviour of Australia's small and medium enterprises (SMEs).
http://www.about.sensis.com.au/media/pdf/SBA-Archive/sba/sbi/2008/November2008SensisBusinessIndex.pdf
You will notice that it covers all states and most industries.
Once you identified the performance of your market segment of interest, you can view an indepth research report here:
http://www.ibisworld.com.au/
Now for the good news: These reports are expensive but can be viewed at now charge at your nearest WA Small Business Development Centre
http://www.sbdc.com.au/drilldown/drilldown.asp?refid=5