To what level does success happen because of education?

I think this kind of depends on what definitions of 'success' and 'education' you run with. If you define success quite narrowly as monetary gain and if you define education narrowly as accreditation through an education institution then generally speaking, more education tends to result in more goodies. However, even given these narrow definitions, it's a piece of cake to list a multitude of ridiculously successful people who never completed formal education. Now, if your definitions of success and education are broader, I think the correlation is a little flimsier. Success in life depends on many things. It's an oddly elusive soup made up of your attitudes, the way your society works, your family and blind luck. Knowledge is just one small chunk in a complex mix of conditions necessary to acquire success.