The population increased in 2013 by 455,000 or about 7% from the previous year and continued a decade-long trend of rapid growth. The total population in 2004 was 14.213 million. The population gains are driven largely by migration. The population's rate of natural increase in 2013 was a mere 0.441%, based on a birth rate of 8.93 and a mortality rate of 4.52. The gender balance was 51.6% males and 48.4% females.