When I was in high school in New Hampshire (early 80s), the grades were as follows:
93-100%: A
85-92: B
77-84:C
70-76: D
<= 69: F
In Ireland (and I think the UK), exams were much harder when I was a student in the 80s and 90s, and were written so that getting everything right wasn't expected or generally possible:
70% + : "First or I." High and rare-ish.
60-69: "Two one or II. Still a very high mark. Often a cutoff for getting into Ph.D. program.
50-59: "Two-two or II.2." A decent mark.
40-49: "Third or III" You passed.
A friend's mother had gone to Oxford on the late 50s/early 60s. She told me that back then, Oxford had a fourth that was also a passing score. Think she called it something akin to a gentleman's D-- (I don't remember her actual term, but mine captures the spirit of what she said).
