[fwefwwfe]

6 different overlapping lines like that make it easier to read? It's amazing what people chalk up to personal preference.

[gghhvgx]

If you have a better hypothesis as to why the authors chose a line graph over a bar graph, I'm all ears.

In the meantime see comment upthread for a rationale[0]

[0]: https://news.ycombinator.com/item?id=14555853