Take these hearsay stats as facts since they will probably be the closest thing to an actual number since the NBOME is so close lipped about the entire evaluation process.
90-95% of you will pass.
Of the 5-10% of you who fail, half of you will pass the second time around. Of course better in mind, you probably did everything correct during your first time. They just didn't make their revenue quota.
Third time takers are rare, but they do happen. Look, if my friend, who speaks VERY broken English can pass during their second time around, anyone can.
I have no way of substantiating these numbers since the NBOME refuses to give out the exact numbers and will never thoroughly explain the method of their evaluation. You WILL NOT get a full explaination of your results. You will only know these words: BIOMECHANICAL DOMAIN and HUMANISTIC DOMAIN, and which one you sucked at more.
Good luck to you because I truly believe that it is more a lottery of who passes rather than actual clinical acumen.