Best way to get representative figures, is to do this kind of research on a computer nearby, but in no way connected to your own e.g. internet cafe, bar/hotel with wifi, library etc.
Another way it use a separate browser with all the settings left blank. Not quite as good, but will do for day to day use.
Sites don't have keywords in this respect; it all depends what users type in, and a lot of users are not computer literate.
The best one I ever got on my heating engineer's website was: "My boiler is broken. I live in London. Can anybody help?"