Brown. The base color of every iris is brown. The thicker the layer of brown pigment is, the "browner" the eye looks, while a thinner layer of pigment leaves the iris blue. Additionally, there are green pigment granules in some irises, and again, depending on how much green is present, the eye can have a hazel or green color. Eyes can also be pink if there is little pigment (albino).
Brown. It's brown! Google it! It is very interesting and eye color is not due to what you think it is! Great question.
Brown. The majority USA population has brown eyes. It approaches 100% in Asians and Africans and Native Americans. Lighter colors are more prominent in Northern Europeans and Asian populations in Russia and associated countries.