Actually Mr Newton
The grading scale in the US is as follows:
A = 90% and above
B = 80%-89%
C = 75%-79%
D = 70%-74%
Failing is 69 or below

This grading scale has not changed in more than 30 years. I'll have to do some checking around to see when this grading scale came into being here. However, there were a few years in the 80s when some schools raised the bar and made anything under 75% failing while an A was 93% and above.

And "Fall" is a term colloquial term that is based on leaves falling off the trees in Autumn. Children are taught "Autum" in school when learning the seasons in kindergarten (that is age 5), whereas they are NOT taught that 'fall' is a season, but rather that "fall" means "to drop to a lower positions".
( flirting with badgers What? It sounded good at the time., Sun 23 Nov 2008, 17:45, Reply)