Niger has an estimated 14 million population, 18% of which are nomads and only 5% of which are urban citizens. Life expectancy at birth is 42 years for men and 43 years for women. The average population density is 12p/km2, which is heavily concentrated in the south and unevenly distributed throughout the nation. With high fertility and mortality rates, the median population age is only 16 years. The official language is French, with many other native African languages spoken, including Hausa and Djerma. Fifty-six percent of the population are ethnically Hausa and 22% are Djerma. An overwhelmingly large proportion of the population are Muslim (over 80%), and the rest are Christian or animist.