So, if I start an average startup today, with an average team and an average idea, how big is the chance that it will be a success within five years from now?

I know this is a very hard question, because it depends on so many things, and it is also kinda hard to come up with a good definition of what a startup is. Perhaps a good definition of a startup is a company that has received funding (and therefore some kind of external approval/stakes in it)?

But let's discuss anyway :)