Dashboard not allowing pie chart as a chart option

Hi, I am trying to get this into a pie chart to show total number of pieces of art in certain stages. It is visually more understandable as a pie chart and to also see the percentages in each stage. For some reason when I had to redo my report, it now won't let me select pie chart. Why is this? I have tried everything and cannot get it to show up. Attached is screenshot of my report.