DAX Calculate the YOY score change

In Power BI your pivoted (Excel) table will get you nowhere. Be sure to unpivot all your "YYYY Score" columns in PowerQuery first. This should give you something like:

Next create an explicit measure for your score:

Max Score = MAX('Table'[Score])

With this you can now create your desired "Score Change":

Score Change =
VAR cursor =
    MAX ( 'Table'[Year] )
VAR prevYear =
    CALCULATE (
        MAX ( 'Table'[Year] ),
        'Table'[Year] < cursor
    )
VAR prevScore =
    CALCULATE (
        [Max Score],
        'Table'[Year] = prevYear
    )
RETURN
    IF ( NOT ( ISBLANK ( prevScore ) ),
        [Max Score] - prevScore
    )

Finally put the results in a matrix visual or a line chart: