Dynamic 100% stacked column chart

Hello @adamwakatsuki. Try this...

Percent Students With Failing Grades = 
    VAR TotalStudents = 
        CALCULATE(
            DISTINCTCOUNT(Marks[StudentID]),
            FILTER(
                ALLSELECTED(Marks),
                Marks[School Year] = SELECTEDVALUE(Marks[School Year]) &&
                Marks[Term] = SELECTEDVALUE(Marks[Term])
            )
        )
    VAR StudentTermSummary =
        SUMMARIZE(
            FILTER(
                ALLSELECTED(Marks),
                Marks[School Year] = SELECTEDVALUE(Marks[School Year]) &&
                Marks[Term] = SELECTEDVALUE(Marks[Term])
            ),
            Marks[StudentID],
            Marks[School Year],
            Marks[Term],
            "FailingGrades",
            CALCULATE(
                COUNTROWS(Marks),
                Marks[Mark] IN {"D", "F"}
            ) + 0
        )    
    VAR StudentsWithFailingGrades =
        CALCULATE(
            DISTINCTCOUNT(Marks[StudentID]),
            FILTER(
                StudentTermSummary,
                [FailingGrades] >= SELECTEDVALUE('Number of Failing Grades'[Number of Failing Grades])
            )
        )
    RETURN

DIVIDE(
        StudentsWithFailingGrades,
        TotalStudents,
        BLANK()
    )

I hope this helps! 🙂