In August of 2006 AOL leaked millions of search records. Some SEOs scoured through this data to look at click data by ranking. A comment on Jim Boykin’s blog reveals the percent of clicks for each position for 9,038,794 searches and 4,926,623 clicks. Donna Fontenot shared the relative click volume of lower ranked results relative to the top ranked site.

1. 42.13%, 2,075,765 clicks
2. 11.90%, 586,100 clicks
3. 8.50%, 418,643 clicks
4. 6.06%, 298,532 clicks
5. 4.92%, 242,169 clicks
6. 4.05%, 199,541 clicks
7. 3.41%, 168,080 clicks
8. 3.01%, 148,489 clicks
9. 2.85%, 140,356 clicks
10. 2.99%, 147,551 clicks

An eye tracking study in 2004 by Cornell University revealed similar results:

Now based on this knowledge, we only need one more input to determine traffic when we get a position anywhere from 1 to 10 in the SERPs, that is the Average Daily Impressions. We can get an estimate of this from Adwords Tools, but if you want to get more accurate numbers, you have to spend a little research money and buy PPC ads. This will give us a more accurate number of daily impressions.