ken_b - 7:20 pm on Nov 26, 2011 (gmt 0)
This bugs me no end. You made an assumption, intentional or otherwise, that you could skip including the information that Grade or "Grade Level", which was not universally included in the charts would be understood by the readers in this context and generalized to all the examples listed.
There is little, if any, rational reason to make that assumption in the context of writing on a forum like this. Especially when it is well known that for a good many members here English is not their first language.
I suspect that a simple sentence such as, "In the charts below, The numbers shown refer to educational level (Grade) such as K-12 and beyond." would have provided enough information to make the charts useful without further explanation.