I'm in Arizona and my wages are being garnished for a state tax debt...how much are they allowed to take?

The law for garnishments in AZ is 25% per pay period, but if it's state or federal taxes they can sometimes take out more then that. I calculated it from my last pay stub and it looks as though they took 36%. Is this a flat rate or will it change? As long as I can still pay rent and electric...I could give a rats behind about anything else.