Well, I can see that you are curious about what you asked. So as far as I know, among the 7 billion population in the world, about over 1/3 of them are black eyed, and they are mainly comprised of Chinese people, Indians, Africans, etc. So you can now imagine how many people have black eyes due to anthropological reasons, and you could get further information from the library or internet.
Brown is the most common eye color in the world with over half of the population having eyes with this color. The pigment with high amount of melanin causes dark hair, skin tone as well as brown eye color. If the darkness of the eye color reaches a certain level, the eyes will appear to be black. In all parts of the world including Africa, Southern European, Asia and Latin America, you can easily find people with brown eyes because the brown gene is dominant among human beings.
Well, for this question, I have to say that it is hard to answer it, for there are many different eye colors in the world, and they are various. For example, for our Chinese people, we have black eye color. And of course, we will think that black eyes are the most common ones. But on the other hand, for Europe, people have many various eye colors, such as blue, gray, and so on. So it depends on where people come from.