This kind of thing is a part of the problem of why America is "dumbing down." Bill is proposed in Morth Carolina.
This article describes a bill (House Bill 145) that would change the way North Carolina schools are evaluated, not the way students are evaluated. Either way, the percentage change in itself is meaningless until you know what standards are being evaluated, and how they are being evaluated.
I'm passionate about this topic! Let me tell you what's currently happening. Students don't just receive F's when they neglect an assignment. They get 0's instead. Do you know what happens to the grade with a 0? It means students can get B's on many of the assignments and that single 0 will bring the overall percentage down to a D.
O's are not only punitive but unforgivable.