I don't know the numbers, but surely it must be quite a small percentage. I'd guesstimate around 0.1% at the most.
My take on the root of the problem is that too much is given too easily, that is the people rioting haven't ever had to work for anything they've got.
I say 'rioters', it's not right to lump them all together. There are those who want to do random violent acts - I won't pretend to know why because my thinking is too far divorced from such people. And then there are the majority of rioters who want some free loot and think this is their chance to get away with it.
Most of us like to get something for nothing, but the difference between us decent people and the rioters is that we don't think it's OK to disadvantage other people in order to get that something.
One thing I can imagine is frustrating - though I in no way think this is a valid mitigating factor - is growing up in a society where you know the chances open to you are always going to be limited. I've always had the chance and motivation to work harder if I want to do better in life.
In the meantime, I wish the police would grow some teeth and deal with this unacceptable behaviour.
I'm not singling your words out in particular Ozz, I just wanted to stick my oar into the debate!