No one knows...
But the algorithm they use is:
They take the top 1% candidate. Work out the bottom score of this top 1% group. The passing score is an (undisclosed) percentage of this score.
If you are borderline fail, they will take a look at your ethics score. If you do well there, they may pass you.
This is done because the top 1% is very consistent from year to year.
A good rule of thumb is - if you score 70%, you should be confident of passing.