Some members of my training group are VicPol and we speak about this issue on a weekly basis...
yes; there's been a surge in the numbers of attacks perpetrated by "specific ethnic groups" but that being said - many of our LEOs also noticing a huge number of copycat crimes that are committed by Caucasian offenders. In fact - Apex distributed a huge proportion of their ill-gotten loot through an Aussie housewife and their ranks have swelled due to an influx of Anglo kids that have been recruited through social media.
I'd like to offer a personal perspective and give a ratio just from what my circle of friends have experienced. Hope no one takes offense - the ethnic descriptions are purely for reference.
1 - close mate's friend got his Subaru WRX carjacked by a fake police car and had a shotgun pointed at his face. Weapon was not discharged. offenders were Sudo. (made The Age). Incident occurred in Ferntree Gully
2 -Relative of a business partner of a mate died twice (once on his doorstep with his wife watching and again when he arrived at the Alfred Hospital) - was revived and placed in induced coma. Injuries sustained - multiple wounds due to kitchen knife. Offender - Aussie. Also made the news obviously.
3 - Pregnant woman (early 20s and a friend of one of my training group students) was pushed over and got her car jacked in Wheelers Hill Melb (no more than 200 metres from a club house that we actually train in) - offenders were Apex (Sud0)
4 - One of my new students had his son jumped by a gang of youths and had phone/wallet taken. Offenders: Sudo
5 - Best mate got jumped on the train on the way back from festival - offenders: Aussie. PSOs tried getting police involved but they wouldn't even pull camera footage because they couldn't be bothered.
6. Close friend got knocked out and robbed in the CBD of Melb - offenders were Euro/Aussie
7. I myself was the target of an armed robbery (granted I was in Sydney at 2am walking around the casino) - but that situation was diffused - all good. Offenders: Asian
Can't remember more (I'm sure there are a few examples I've left out) but I guess the ratio isn't exactly good...
I suppose we can start pointing fingers at particular ethnic groups (I'm as guilty as the next guy because it's pretty obvious what the trend is) but they all know their rights and will readily accuse law enforcement of racism the minute accusations are leveled.
Guess all we can do is to be more careful and get some training if you're really concerned.