The birth rate ranks seventeenth highest in the world at 4.95 children born/ woman as contraception is uncommon and infant mortality relatively high. 45% of the population is aged 0-14 years old forcing the median age as low as adolescence (17.4 years).
95% of mainland Tanzanians are ethnically African, with cultural roots predominantly tied to one of 130 Bantu tribes. Zanzibar has a greater Arab influence, where more than 99% of the population are Muslim.