AT Museum manager Joe EarthTone Harold did an informal social media survey of hikers earlier this year, to learn about the sources of trail names on the Appalachian. Of 223 respondents, 77% said they had a trail name. Of these, 80% had been given their name and 20% chose their own.
When creating a formula that should return a percentage value, you will need to format the field correctly to get the % sign to properly show. Right-click on the field in question, select Format Field. Click the Display Currency Symbol checkbox. Click the Customize button. Click the Currency Symbol tab.
One easy way is to use a custom number format that provides no format for zeros. The two pie charts below have General and 0% number formats for the values and percentages of each pie slice. Notice that each has an entry for item C in the legend.