The common figures (google/facebook for examples) are typical college graduates from a very top school, who happened to drop in the last year of bachelor or master to found a company, sponsored by their university network and connections.
By the way I was talking having having a formal education versus no formal education and you're trying to move the conversation to dropouts. Dropping in the last year of a top US school (because you were given half a million dollar to form a company) qualifies as having a formal education.
What about three years?
Two?
One?
We know zero higher education doesn't meet your standard, and 3.5 years does, so I'm trying to figure out where you draw the line.
Knuth, Dijkstra, Kernighan, Ritchie, etc. all had degrees, although some are non-CS because CS degrees weren't a thing back then. Linus Torvalds, Dave Cutler, and Theo de Raadt all have degrees. The only hardcore coder (i.e. not a business person) without a degree I can think of is John Carmack.