Short bio: Computer Scientist, FOSS supporter (read more)
Tux Machines (TM)-specific
We recently looked at the commenting practice of active working open source projects. It is quite impressive: The average comment density of open source is around 19%. (Comment density = comment lines / (comment lines + source code lines)). That is much more documentation than most people thought!
However, such a rough number needs discussion. Here, I look at the comment density on a programming language basis. As it turns out, the comment density of active open source projects varies by programming language. Java is leading the bunch, but that needs further discussion.
Below, for six major programming languages, you can see the average comment density as well as its distribution (cast as a histogram).