I live in a NE town with two prep schools and a really good public high school. All three post their school’s grading/academic profile on line and send it to colleges. It’s easy to compare them. One of the schools even lists the exactly grade distribution for the class by discipline, e.g., Science A (42), A-(51), B+ (36), B (27) and so on down to F.
All three list their SAT and AP results, so it’s easy to see where the competition for grades may be toughest.
One of the prep schools has this bolded on their profile: