Saw a statement in the ezine from Seda Communications regarding ah-ha.com figures. Apparently the top three pay-per-click advertisers receive 78% of click-throughs & the #1 advertiser gets three times the number of click-throughs over the #2 advertiser. The top five bidders receive 87% of click-throughs.
Similar figures for AdWords?
Highly doubt that the top few AdWords get 78% of the clicks and top-5 get 87%. The top 3 and 5 editorial and AdWords listings combined may get those numbers.
The ones down the side vary with the number of ads displayed and also the quality of the SERPS. For bad SERPs and no competition, I have seen CTRs of 15%. When it's hyper competitive, a good CTR would be 2%, but you have to be right on topic to get that. There's also no doubt that the top 3 or 4 positions get better CTR as the lower positions don't display on small monitors without scrolling.