Age and sex structure of the population

Just over half of the New Zealand population is female (51 percent in 2009). Although there are more males than females born and males outnumber females among children and youth, the sex ratio changes in adulthood. For example, in the year to December 2009 there were more females than males in every age group from 25–29 years onwards. The sex ratio dropped from 105 males for every 100 females at ages 15–24 years, to 93 males per 100 females at ages 25–49 years. This reversal reflects higher mortality among males, particularly at ages 20–29 years, and sex differences in net migration at the peak migrant ages of 25–49 years. At older ages, the difference reflects higher male mortality rates.

The New Zealand population is ageing: the median age of the total population was 37 years in 2009, and it is expected to rise to 39 years in 2026.¹¹

The proportion of the population under 15 years of age has declined from 23 percent in 1991 to 21 percent in 2009 and it is expected to fall to 19 percent by 2026. The population aged 65 years and over has increased from 11 percent of the total population in 1991 to 13 percent in 2009. It is expected to reach 19 percent in 2026, the same share of the population as children.

Figure P4 Age distribution of the population, 1991–2026

Source: Statistics New Zealand

Age structure varies by ethnic group. At 30 June 2006, the European or Other population was the oldest, with a median age of 38 years, followed by the Asian population (28 years), the Māori population (23 years) and Pacific peoples (22 years). By 2026, half of all Māori are projected to be older than 25 years and half of all Pacific peoples will be older than 23 years. Over the same period, the median age of the Asian population is expected to rise to 35 years, while for the European or Other population it will rise to 42 years.¹²

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