Pie and Donuts Charts are a great way to visual data as a percentage of a total.
To create a Pie or Donut Chart:
Create a new visualization.
Choose the Pie or Donut icon.
Select which column will serve as the Color for your chart. Each value represented in the column used in the Color field will be its own color on the final chart.
Select which column to use in the Value section of the chart. The column in the Value section will be used to determine the size of each colored section of the chart. The column can either be aggregated using the Value field in the chart, or can be a column of pre-aggregated values.