For first time US students the pass rate was 96%. However, they did change some of the grading criteria last year, so it may have dropped somewhat. Whatever the case, the odds are still heavily in your favor. I think you need to have made major mistakes consistently to fail the exam. My take is that if you make minor mistakes here and there you will do fine. They have to realize how artificial this exam is, and that minor mistakes due to pressure and time constraints are inevitable. But if you are repeatedly making large mistakes, then you are probably at risk. I know that I personally made many small mistakes, and possibly one or two larger oversights. I passed, and I think the majority of others have very similar experiences.