Graph doesn't place average per year correctly

Hi!

Based on your description and the DAX formula provided, I see a couple of potential issues:

1. Naming Convention: The way you've named your tables and columns is a bit confusing. For instance, having a table named 'amount of unique visitors' and then a column within that table named '[amount of unique visitors]' can be misleading and cause potential mistakes.

2. AVERAGEX: This function averages the results of an expression calculated for each row in a table. It's important to ensure that the expression used inside AVERAGEX is accurately capturing what you want to average. In your case, you're just referencing the column, which might not be yielding what you intend.

3. ALL function: When using the ALL function in conjunction with FILTER, you're effectively removing any filters on the Datedimension[Datekey] and then reapplying them based on the conditions you specified in the FILTER function. It's not inherently wrong, but it's worth noting in case there are any other filters being applied elsewhere in your model that you would want to consider.

Let's try to address the problems and refine the formula:

AverageUniqueVisitors2016 = 
CALCULATE(
    AVERAGE('amount of unique visitors'[amount of unique visitors]),
    FILTER(
        ALL(Datedimension[Datekey]),
        Datedimension[Datekey] >= DATE(2016, 1 , 1) && 
        Datedimension[Datekey] <= DATE(2016,12,31)
    )
)