How to change number formatting

Are you trying to represent percentages but instead of 2,15% – as you added your numbers in the data – your visualization is showing 215 as a value? 

You will need to change the number format.

    Switch to the Data tab and check what type of decimal separator your data uses. In this example, it's a comma.

    Switch back to the Preview tab and go into the Number formatting settings. Here, make sure that the decimal separator matches the one used in your data.

    If you would like to display your number as a percentage, you will have to add a suffix. You can do this under "Number styling" > "Suffix".