Only 5% of the excellent programmers are in the US if you assume that all the factors that contribute to excellent programmers are randomly distributed. It's a statistically fallacy. I wouldn't expect most of Africa to produce many excellent programmers due to the large uneducated population. I also wouldn't expect China, or India to produce a directly proportional ratio of excellent programmers ether due to the massive illiteracy rate in their populations. I also wouldn't expect Middle Eastern countries with massive uneducated female populations to be able to produce the same ratio to their populations. I would expect the US, Japan, South Korea, and Europe to produce most of the worlds 5% of assumed excellent programmers due to the higher rate of educated citizens. There are a lot of assumptions, and unless you know all the variables involved, or made the necessary measurements you could also assume that 90% of the worlds top programmers were born and raised the any random country you pick, including the USA.