Red-This is the most common color. Passports with a red cover are often chosen by countries with a historical or current communist system.
Blue-This is the next most common color. The blue cover symbolizes the "new world".15 Caribbean countries have blue passports. Within the block of South American countries the blue passport cover symbolizes the connection with Mercosur — a trade union. This includes Brazil, Argentina, and Paraguay. Venezuela is the exception here: it also belongs to the union, but its citizens have red passports. The passports of US citizens were changed to blue only in 1976.
Green-Most Muslim countries have green passports
Black- The rarest passports are those with black covers. These can be found among the citizens of some African countries — Botswana, Zambia, Burundi, Gabon, Angola, Chad, Congo, Malawi and others. Citizens of New Zealand also have black passport covers, because black is the country’s national color.
