Hi can anyone tell me how much income you have to earn before FTB a and b are decreased?

I am a stay at home mum, not working. Hubby is the bread winner and our estimated income is $60,000. As far as i know we recieve full FTB a and b. Is this right?? I think i read somewhere that the FTB a starts to decrease once the income reaches $72,000 or something like that??
I'm just trying to make sure we're getting the correct amount.
cheers