Google's new Google Trends service provides information on how frequently different terms have been searched. Interestingly, it seems that the volume of searches on "polygraph" is lower in 2006 than it was in 2004:
http://www.google.com/trends?q=polygraph
Also, for reasons that I find baffling, the #1 region from which "polygraph" is searched is -- far and away -- Sacramento, California. Numbers 2 & 3, Reston, Virginia and Washington, DC are more readily understandable. :)
It also appears that searches on "lie detector" have fallen off since 2004:
http://www.google.com/trends?q=lie+detector&ctab=0&geo=all&date=all
Again, the #1 region searching for "lie detector" is Sacramento.
The heavy weighting of Sacramento seems to date to 2004. Restricting a Google Trends search on "polygraph" to the United States in 2006:
http://www.google.com/trends?q=polygraph&ctab=0&geo=US&date=2006
Washington, DC takes the #1 spot.
For 2005:
http://www.google.com/trends?q=polygraph&ctab=0&geo=US&date=2005
Reston, Virginia was #1 and Washington, DC was #2.
By the way, those who do a Google search on "polygraph" are likely to find AntiPolygraph.org as the #1 or #2 search result.