@David Matthew - actually kind of fascinating; the fall of the gothic minuscule mapped out. I wonder if those tiny bumps around 1920 and the 90's to 00's reflect anything?
The strange bumps at the beginning of the century for phrases you wouldn't expect to occur then seem to be from periodicals. If a periodical was first published in 1900, it seems it logs all issues of that periodical as having the date of the first one (or at least that's what my experiments with "genetic modification" indicate).
Words such as Jedi, had other uses (it seems to crop up a lot in Shakespeare's Coriolanus, because it is a mis-scanning of AEdi, short for AEdiles), and Wookie is an English surname (unlike Wookiee).
You can click on the links below the graphs to see the publications where the words are used.
That's what I meant earlier. The answer is that the software misreads characters in the pdfs. If you click on the links, you get the individual references.