Using Google Ngram to Track Use of the Word "Terrorism" Between 1800 and 2008

If you haven't wasted a few minutes playing with Google Ngram, you've got to give it a ride.  The basic idea, as I understand it, is that Google has put together a vast database of every word in every book (from 1800 and 2008) that they've digitized, and you can just put in a particular word or phrase and get a graph showing how often it appears as a percentage of the words in the database for that year.  Here's what I got when I plugged in "terrorism" in the "American English" database: About what one might expect.  The trend line begins picking up mid-century and runs steady through the heyday of terrorism associated with anarchist and syndicalist movements, spikes a bit with the post-WWI red scare, builds gradually through the WWII and early Cold War eras, spikes dramatically in the late 1970s-early 1980s during the Tehran hostage crisis, falls back some but not all the way during the 1980s and 1990s, and then zooming upward after 9/11. The same search in the "British English" database generates close to the same pattern, except for the presumably-Ireland-related spike in the early 1990s: And just for kicks, here is "terrorism" in the "English Fiction" database.  Seems to track the larger pattern quite closely: Finally, just to show not all the trends go up, here is "declaration of war" in the all-English database: