Here's my attempt at the graphic. I tried not to read too much into the initial challenge or data, so this is my take:
- Clean up the title-it had to make sense.
- Use only the original table-I didn't want to change the general goal of the original poster.
- Leverage how people tend to view politics today (thanks to the MSM)-so strong use of left/blue/democrat and right/red/republican.
- I chose to keep the bar graph since the data had points in the gap for which there is likely more information (e.g. non-presidential election years).
- The gaps between each bar is equivalent to the number of intervals between. There are three bars width between each bar, one for each non-represented year.
- Finally, I tried to Tufte as much as possible removing irrelevant axis and grid lines.
I hope you enjoy.