Fig 16. Normalized frequencies of references to years.
The top panel resembles a figure from [1] using unfiltered data from English Version 2. (The cited paper uses Version 1.) Note the characteristic rapid rises and gradual declines, as well as the increasing peaks in yearly references. However, while the characteristic shape is still present in fiction (Version 2, bottom)—at much reduced levels—the peaks do not rise. The rising effect is likely due to citations from scientific texts.