Most every affiliate works with a number of different affiliate programs. Some work with a lot of different programs.
Like everything else in life, some affiliate programs work better for some affiliates than they do for others. And most affiliates will earn most of their revenue from just a small number of affiliate program relationships.
Looking at your revenue over the past year, and the affiliate program with whom you made the most revenue over the past year, vote which percentage of your revenue came from your top performing affiliate program. Did you get 25% of your revenue from that top program? 50%? Or more or less than that. Besides voting in the poll feel free to post the program you've found to be the best for your site.
Michael