According to a friend of mine in California who went through the process. Grading on the bar exam there is simple. On every test, 50% pass and 50% fail. You either make the cut or retake the test. Somewhere around 70-80% of people fail to pass on the first try if I recall correctly.
He was not much fun to be around when he finished law school and was cramming for the bar. He passed it on the 2nd attempt.