My distance contribution to ggplot2 day 🙂 http://rpubs.com/rosemm/cond_density_plots
The example is with some real data of mine, which I can’t share with you all just yet, sadly. You can apply it pretty quickly to other data, though, for example:
ggplot(diamonds, aes(carat, ..count.., fill = cut)) +
geom_density(position = "fill")
This post (http://stackoverflow.com/questions/14570293/special-variables-in-ggplot-count-density-etc) has some information about the weird ..count.. thing going on in the aes() mapping, for those who are curious. I also encourage you to play around with the adjust argument in geom_density() to see how that changes your plot. Have fun!