I would advise you to have a look at gradstats for some valuable statistics. Here is a link to one of their reports: http://www.graduatecareers.com.au/wp-content/uploads/2015/12/GCA_GradStats_2015_FINAL.pdf
Statistics only tell half the story - for most science careers you'll need an additional qualification to actually be 'employable'. This is may be a professional degree (e.g. MD, DDS, etc) coursework Masters or research Masters. In my field, you pretty much need Honours as a bare minimum. The three year degree doesn't give you the research/lab experience, nor the 'soft skills' (writing, presentation, data analysis, etc) you need to actually get a job (which is a failing).
So the fact that it's pretty much just looking at three-year degree recipients, when most people need an extra degree to become 'employable.' In
most fields (speaking broadly here, not just science,) a three year degree isn't enough any more. If you're interested in a career in science (not just research) you'll be spending four (BSc+Hons) to five (BSc+Masters) at university minimum. That's if you don't use it as a launching point for a professional Masters.
It should be stressed that the (three year) BSc at Melbourne Uni basically assumes that you'll be doing a Masters to pick up those technical/soft skills if you want a career in 'science'. A three-year degree isn't really all that employable.
Anecdotally most of the people I knew that went through Honours with me found
something (or were successful in getting a PhD scholarship). Of course, that's just my experience - if you go through your Honours/Masters and do poorly, you might find it hard to get a job.
Likewise, there's more to science then just 'research', which is a pretty broad thing anyway. There's jobs in QA/QC, industry (which can be 'research,' or jobs in advanced manufacturing), diagnostics, (scientific) sales, etc. You probably will be (mostly) working in a lab for the first part of your career, though.