Radar Chart - How to allow data overlapping with choice of list-box

[#1]

Question:

1. There are three years of monthly sales data.

2. There is a list box to allow user to choose which year to show in the chart.

3. Currently, I have a radar chart, which allows to show one year of data at one time. How can I configure the chart to allow choosing multiple years of data via list-box overlapping in the chart as follows?

Dimension: Month

Expression: Sales

Thanks in advance.

[Gysbert_Wassenaar · Accepted solution]

Add Year as the second dimension to the radar chart

[#3]

Thanks, Gysbert. It works perfect.