'Declaration

Public ReadOnly Property GradeValue As Single

public float GradeValue { get; }

public: __property float get_GradeValue();

public:
property float GradeValue {
   float get();
}

This grade is numeric basis for expressing quality grade on a descending scale from 4,0 to 0,0 in steps of 0,1. The highest quality is represented by 4,0. The unavailable value is represented by negative number.