If done properly with a good design, fonts and layout, you could see anywhere from 5-12 percent CTR. However I'd sooner have a strong call to action affiliate link at the bottom that could bag me a $20 sale.
I see that you have a health related article directory. May I ask how much money are you making from it?
you can try affiliate programs such as hosting, It's much better than adsense if you don't have a decent traffic.