Add markers to dynamically highlight relevant data points in a series.
You don’t need a dummy series to add markers: you can simple select a data point and change several properties, including adding or removing markers. The advantage of using a dummy chart is that these markers can be dynamically configured (minimum, maximum, last, specific date…).
The formula checks if the lookup table contains the current year. If so, it gets the data point, if not, adds NA().
Formula for displaying the dummy series: