According to the National Bureau of Statistics, Nigeria has a large base of young population- more than 54 percent of all males and more than 51 percent of all females are younger than 20 years of age.
The share of males and females in total population is roughly equal: 49.2 and 50.8 percent respectively. This pattern is similar across rural- urban areas and across the states, except for Enugu state, where ratio of males over females is only 0.82.
The average household size in Nigeria is 5.06 persons per family: in rural areas the size is higher – 5.42 individuals versus 4.50 in urban areas. The highest household size is in Jigawa state- 8.15 persons and the lowest is in Ekiti state where on average the household is composed of 3.50 family members
The total dependency ratio in Nigeria on average is 0.97. The highest dependency ratio is in Jigawa state at 1.40 and the lowest is in Lagos with 0.63 of dependents per 1 working age person.
On average 18.8 percent of households in Nigeria headed by female household member. That share is generally higher in urban areas- 21.4 versus 17.1 percent in rural areas. The lowest share of female headed households is in Niger state with only 1.9 percent and highest is in Ebonyi with 36.0 percent.
The share of females, among those older than 12 years of age, in monogamous marriage is 41.9 percent versus 36.7 percent for males. The share of males and females in polygamous marriage is roughly equal at around 9.9-9.6 percent respectively. The polygamous marriage is more widespread in Jigawa state where 15.1 percent of males and 32.8 percent of females report being in polygamous marriage. The lowest rate of polygamous marriages is in Akwa-Ibom, with less than a percent of males and females entering polygamous marriages.

Data source: National Bureau of Statistics

Image Credit is to World Economic Forum