I would be interested to see how they created the graph, but I couldn’t find it at the website in the time I had.
That is easy to determine. They started out with an opinion, then they drew some lines to "support" their opinion. The producers of the chart for whatever reason chose lines that are patently unbelievable. The "scientific advancement"(whatever that means) fell by about 75% in ~30 years, then remained in absolute stasis for nearly 1000 years.