spot on monarch 'zenden' 330 ('look at me, look at me, i've got epaulettes'),
if you reach the standard your in - so it doesn't really matter what the pass rate is - for any week it could be 100% or 0%!
As for the average success rates, i think both 2 and 3 were fairly low(20-40%) and stage 4 80%. overall it's 2.8% from writing your name on the application form to flight SQ285/321 to sunny(well...kinda) Auckland.
as gary said, theres not much to be done for stage 2 - just try ensure you perform on the day - smile and be positive(easier said than done i know!!)
best of luck folks
