What the bar shows is relevant to the other keywords, not absolute.
Compare what you see in AdWords with: Overture search tool.
And KeyWorddiscovery (try a few alterntives here, countries etc) to get a rough estimate. If you know a unique keyword well (your own site or brand name for example) you can infer pretty well the totals on other keywords. Play around for a while and you will get a feel for this.
[edited by: eWhisper at 5:16 pm (utc) on Jan. 10, 2007] [edit reason] Please don't drop links - See TOS. [/edit]