Haven't done the maths on tax brackets before?
$17,550 plus 37c for each $1 over $80,000
$54,550 plus 45c for each $1 over $180,000
On the first 80K you only pay $17,550 in tax, 17550/80000 = 0.21 per dollar until you earn $80,001 p/a
180,000 - 80,000 = 100,000. - this is the bit you get charged the 37c on.
100,000 x 0.37 = 37000.
So total tax paid is 37000+17550= 54550 or the minimum amount for the next tax bracket.
So the actual rate of tax for someone earning $180,000 p/a is 54550/180000 which is 0.303 or 30c to the dollar.
Source mate
Our progressive system works by only taxing you what the people earning less then you are taxed until you earn more then they do. Does your head in a bit, but its fair.