Ah, selective statistics ...
in 1996, we had a massacre at the hands of an unstable armed lunatic which brought the The Firearms (Amendment) (No. 2) Act 1997 into being as the result of a public petition. Sincew then, statistics are much lower than your chosen 2002 figure; 97 firearm homicides in 2002, 50 in 2006. This is a significant decline in firearm homicides, in case you can't tell.
The point about criminals having firearms is that you can use that to spot them. If someone is armed with a firearm, they're a criminal and using a gun in a crime will elevate it from a petty crime from a serious crime. Mere possession of a firearm will get you a mandatory minimum 5 years inside.