Of all the billionaires in the world, what percent of them did something like this, vs the percent who reached that number from investments (and by investments

Of all the billionaires in the world, what percent of them did something like this, vs the percent who reached that number from investments (and by investments I mean assets they possessed which ballooned in value)? I'm betting it is a tiny fraction. Most modern "wealth" is all based on investment games.