I really recommend that Inanna and Revenge, you both watch or revisit 'Bowling for Columbine'.
Revenge, you talk of 'crimes in the UK and Australia' not murder with guns. There is a language gap there. Crimes can include things I would not call a crime, like absent minded shop lifting, even real shop-lifting if you are starving. Think of those with mental or with anxiety problems - not that I have done it - but I have been close and I understand how it can happen.
Also in socialist countries crimes may be higher than in capitalist countries, but when Russia freed itself of Communism it took a step back towards poverty, a huge one, and after that Russia terrorized Chechnyans with its state terrorism in fear that they would lose oil rights. That continued and worsened due to Putin being part of the 'war on terror' so-called.
Statistics are lies, because they can prove anything you like as long as you use them carefully, 5 percent drop in crimes. Does 9/11 count as one crime or 3000? (do you see my point) How are they arriving at the statistics - I would like to know where they come from and how they reached them. I think you could prove exactly the opposite point using a different method.
Does 'crimes and criminality' count in all the thousands of blacks in jails in America probably because of their color. Go to a British jail and I bet the statistics of black population and black criminals are almost the same. People do not target people for their color in Britain, it is illegal.
Granted, statistics aren't fool proof... but then neither is Micheal Moore.
My point is, there is NO fool proof system. Systems are designed by humans. Humans are not perfect and therefore neither will any system they create be perfect. The best we can do is find ways to get the most good out of a system while causing the least ammount of harm in the process.