The CAP is difficult to read because it is graphing something unusual. If you sum the values of the green and blue lines, they equal 100%. It's trying to show that gun deaths are more likely to happen to young people, but it loses any sense of proportion. We know everyone dies, but we don't know how many people die from gun deaths.
I improved it by breaking all deaths into 3 categories - gun violence, non-gun violence, and natural. It's still a little unusual to be graphing 2 different things on the same graph, but now the blue, yellow, and gray lines act as a zoom in on the yellow line. I think there is still a better way to visualize that zoom feature.
Update: Instead of graphing percentages, I realized absolute numbers tell the story better. By using a log scale, it kept the graph readable.