AdSense doesn't reveal how much of the amount of money that the advertiser pays goes to the publisher. Furthermore, value per click varies depending on the keywords that your site is optimised for. In general, it seems that finance-related advertisements (loan, credit, business, etc) seem to yield a higher income per click than most, probably due to the fact that financial institutions have more money to throw at marketing and advertisement.
On a funny note, couple of days ago, I saw an AdSense advertisement for a Chinese laundry service in New York, complete with the lady's phone number. Wonder how much a click on one of those was worth...