goodroi - 1:30 pm on Oct 6, 2011 (gmt 0)
I am curious how many keywords you have been tracking and for how many months you have been monitoring them. Based on my research I have seen the opposite. Sites that are too heavy in Adsense and/or affiliate ads seem to suffer.
I have found several hundred keywords that have heavy adsense sites ranking high but then I have also found thousands of other keywords where the top ranking sites have minimal or no adsense present.
Personally I do not think there is a direct connection between Adsense and rankings. IMHO I think very high adsense usage on a website is more common among webmasters looking to exploit short term profits. Webmasters that are focusing more on establishing long term properties tend to use less adsense & affiliate ads on their pages and have a higher percentage of content.