The original scale was as follows:

A: Excellent, equivalent to 95— to 100 percent

B: Good, equivalent to 85— to 94 percent

C: Fair, equivalent to 76 to 84 percent

D: Passed, equivalent to 75 percent

E: Failed, less than 75 percent

E was quickly replaced with F, because “F for failed” was more intuitive than “E for … excellent or failed?”