In what countries were the exams only once a year? When I grew up in the 90s in Sweden we would have tests and exams frequently, usually at the end of each module. This continued all the way through university. I think we had 3 separate exams for the first math course (which lasted a quarter of a year, so roughly one exam per month).

(Though they didn't give formal grades for the first several years of elementary school, which I'm not sure was a good idea.)