Google has made known through a post on the official AdSense blog, the percentages of gains that are turned to AdSense publishers.
As for AdSense for content most AdSense publishers earn worldwide, 68% of revenue. That is valid for each click on an AdSense banner for 68% the amount you pay for that click will go to the publishers, the remaining 32% will go to AdSense.
As for AdSense for search to earn publicher, worldwide, 51% of revenue, while the remaining 49% will go to AdSense.
Google warns that these units are not "eternal" and may change over time, although currently there are no changes.

Google also warns publishers from considering only the percentage of income devoted to publishers to choose which network to rely on advertising for their website. For example, the AdSense publishers would receive $ 68 per $ 100 dollars paid by the advertiser for valid clicks on the banners (68%). Relying on an ad network, guaranteeing that for example the publisher 80% of revenue, if it could, however, to collect only $ 50 banner ads on the site publisher would come to $ 40. Publishers who then would have earned less than he earned with AdSense despite the other network capture a share of partnership more than AdSense.

The decision of Google to disclose the share of revenue earned by publishers comes from commitments made by Google with the Authority for the competition and the market after opening a preliminary investigation into the complaint lodged by the Italian Federation of Newspaper Publishers (FIEG) .