We have that all the way through although we do have 5 categories [well below = 2 years plus below, below = one year below, at standard, above by one year and well above. I don't think my school uses well above though and high school uses credit and merit instead of above and well above. But in the 70s at primary school we at +, = and - so below, at above {though it was above average not above standard and I never got grades at high school except in external exams as far as I can recall. Or maybe I did but since passing was only based on the final exam I didn't care.