NAT Vs. PF , which happens first?

[arlen_(_dot_)_fletcher_(_at_)_att_(_dot_)_net]

Didn't see the answer to this in the man pages or the 
various tutorials (though I could have missed it):

What happens first, NAT or filter rules?  I believe NAT 
used to happen before filter rules were applied in ipf.  
Is the behavior the same in pf?


TIA
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