NSA search trends
google.com
google.com
http://www.google.com/trends/explore?q=nsa#q=nsa%2C%20CIA&cm...
This does better at discriminating against bus companies and such.
The steady decline until recently is interesting.
Or maybe one can see a general decline of less popular terms due to the growth and change of the internet usage in the past 10 years? Imagine all those people who search for 'weather', 'email', 'facebook' etc.