You are right; I seem to have copied output from a version which actually calculated the percentage which I don't remember ever even writing. I can't figure out where that came from as I don't have a copy of it anywhere. I can guess that it included assigning some variable, let's say x, to (number_of_es / number_of_letters * 100) and then printing "...of which", number_of_letters, "%s%" %x, "are 'e'." I would test this right now, but interactivepython.org is not responding.