5,131,666 (25.2%) of the population were aged 14 or under whilst 2,525,573 (12.4%) were aged 60 or over, leaving a working age (15-59) population of 12,702,700. The dependency ratio was 60.2%. The mean age was 32 years and the median age was 31 years. The sex ratio was 94 males per 100 females. The fertility rate for married females aged 15 or over was 2.65 live births. There were 5,264,282 households of which 3,986,236 (75.7%) were headed by males and 1,278,046 (24.3%) were headed by females.. Which age group populated the city the least?