BGP AS Sets in the wild

Hi, I was looking at route-views.routeviews.org for the BGP routes and i dont see any AS-Sets whatsoever. Are BGP routes with AS-SETs not generally leaked into the wild? Is this the case? I am under the impression that AS_SETs are generated whenever there are some routes that are aggregated. Is there any other way also to generate AS_SETs in BGP? Any clues. Thanks, Abhishek -- Class of 2004 Institute of Technology, BHU Varanasi, India