private void incrementLetterGradeCounter( int grade ) {
        
        switch (grade / 10 ){
            
            case 9:
            case 10:
                ++aCount;
                break;
            
            case 8:
                ++bCount;
                break;
            
            case 7:
                ++cCount;
                break;
                
            case 6:
                ++dCount;
                break;
                
            default:
                ++fCount;
                break;
        }
    }