Nah its not. Back in the old days, there were only around 22 100's, and then around 45 of the rest. This is because the way they calculated it was that you got 100 UAI if you were above the 99.975th percentile, 99.95 if you were between the 99.925-99.975th percentile etc. So within every 0.05th percentile, there are 50 people. Under the current ATAR, you get 99.95 ATAR if you are above the 99.95th percentile (i.e. top 0.05=~45 people), you get 99.90 if you are between 99.90th-99.95th percentile (i.e. next 0.05=~45 people) etc