Using Excel, I had data that was presented as a percentage, but the source data was not output in decimal notation. Thus, 67.53% was in the original data as 67.53. I wished to graph a pivot table of this data, but didn't want to go through the extra steps to convert the data by dividing it by 100 and re-graphing it.
When going in to the Axis Format and choosing Number, when I chose Percentage, it would multiply the data by 100, giving me 6753% and such on the left axis. That wasn't what I wanted, so I took a leap of logic, diving from my programming experience that I could use an escape character, and walla! It worked! '0\%' displayed the numbers with a trailing % sign without the multiplication.