Making pie chart in numbers for ipad

Hello

I am just getting started with numbers on my ipad. I have 4 columns of data, the first is an ID number column and the other three are checkboxes. I would like to make a pie chart that show's the percentage of rows that have each of the three checkbox columns checked. I am highlighting all three columns to be included in the chart and they all show up in the legend at the top of the chart, but the pie itself is just the color of the first column with 100% in the middle. The data show that 5/10 boxes are checked in column A, 6/10 in column B and 4/10 in column C. Not sure what I'm doing wrong....