I was never convinced by the AOL data showing 42% of people clicked on the number 1 listing. Apparently it was just for organic clicks but that still makes the figure misleading and almost useless.
What most people want to know is the number of people they are likely to get visiting their site if it ranks at number 1. Knowing this figure and your conversion rate it is easy to decide how valuable a number 1 ranking is likely to be and decide how much you want to pay to get there.
Hitwise have kindly provided this figure today when they analysed the GoCompare.com “penalty”. Looking at the chart you can see that for a competitive term such as “car insurance” (full of PPC ads) around 17% of the traffic clicked on the number 1 result.