It's depends on how you are as a person, how hard you are willing to work for it, which skills you learn and how good you are at them, what kind of connection/contacts you have, your family and friends play a major role, LUCK plays a major role, how willing you are to sneak around and do your research, if you're willing to go the extra miles for anything beneficial and so much more.
Or, you could be adopted by Bill Gates.
Realistically.......if you are not a billionaire already.......zero.
Out of 300 million people in the US, there are only 492 billionaires.
That equates to 15/100,000ths of a percent.
Minimal unless you are extremely clever and work hard to get to the top of the tree.
Your chances of winning the lottery are greater.
Statistically it is 1.4 in a million.
