Hello, I'm having fun exploring the pretty graphing options in R, although I'm struggling to figure out how to do some simple things; would be thankful if someone could point me toward relevant sections of the manual or provide some starter code to get me going. I'd like to extend what is offered in the manual here for stacked bar plots: http://docs.ggplot2.org/current/geom_bar.html For starters library(ggplot2) ggplot(diamonds, aes(clarity, fill=cut)) + geom_bar() Which makes a nice stacked barplot featuring counts on the y-axis. I'd like to transform this to fraction or percentage, and (with some googling) came up with this: ggplot(diamonds, aes(clarity, fill=cut)) + geom_bar(position = 'fill') However, I prefer using a line via frequency polygons. Using counts, this is: ggplot(diamonds, aes(clarity, colour=cut)) + geom_freqpoly(aes(group = cut)) I'd like to adjust this to show fraction instead of counts on the y-axis (as in the previous example), but this command is obviously incorrectly constructed: ggplot(diamonds, aes(clarity, colour=cut)) + geom_freqpoly(aes(group cut), position = 'fill') Error: position_fill requires the following missing aesthetics: ymax Any pointers would be appreciated. Best, Jonathan [[alternative HTML version deleted]]