Projected Percent Change by Age

These maps show projected change in the number in each broad age group living in each Territorial Authority Area (TA) for the period 2013-2043, according to Statistics New Zealand’s High, Medium and Low Variant assumptions (Statistics New Zealand 2017, 2013(base)–2043 Update). The maps show how the number in each age group is projected to increase or decrease over time, red shades indicating growth, blue shades indicating decline. The darkest red shade indicates the greatest increase in number, while dark blue indicates the greatest decrease. Paler reds and paler blues in between indicate smaller (that is, slowing) increase or decrease.

Maps are given for the following age groups: 0-14, 15-24, 25-44, 45-54, 55-64, 65-74, 65+ and 75+ years. Maps also given for the ‘prime’ working age population (20-69 years). Percentage change = (number aged X at time t + 5 years - number aged X at time t)/number aged X at time t *100.

Numerical and structural ageing (as in an increasing numbers and proportions of people at older ages and decreasing numbers and proportions at younger ages) is generally progressive in nature. However, the trends are not strictly linear, as there are several ‘population waves’ to contend with, such as the baby boomer wave which in 2019 refers to New Zealanders aged between 55 and 75 years (depending on whose definition is being used). The trends also differ by district—which is what we are trying to illustrate here. For example, at 65-74 years, the medium variant maps for the period 2013-2023 suggest widespread growth in numbers in excess of 20 per cent (darkest red) for 58 districts, and growth between 3.0 and 19.9 per cent for the remaining 9 districts. Between 2023 and 2033, growth at these ages slows in the majority of districts, denoted by widespread shift to paler red and pink shades, and is moderately negative (pale blue) in four districts. Between 2033 and 2043, the majority of districts experience decline in population numbers at these ages; only one district (Queenstown-Lakes) is projected to have a significantly increasing numbers at these ages (dark red), and just eight to have moderately increasing numbers (pale red); all others have moderately decreasing (pale blue) or substantially decreasing (dark blue) numbers. The reason growth at these ages slows and becomes negative in most districts is because the ‘baby boomer’ wave is currently moving into and through this age group, and will move on into the next one (75+ years), where growth can be seen as widely positive—although also slowing across the three decades. For planning purposes, this diss-aggregation by age, over time, and by subnational geography is critically important, because it contrasts with the overall picture (map for 2013-2043) of substantial growth at these ages, but without any indication of whether that growth is slowing or increasing, and whether or how this differs across the country. Responding to New Zealand’s demographic diversity efficiently and effectively depends on understanding these trends.

While the raw data underlying these maps have been drawn from Statistics New Zealand, any calculation and interpretation errors are those of the author.

The high, medium and low assumptions regarding the total fertility rate (TFR), life expectancy at birth (by sex), and net migration for each TA are available from:

References and further reading

Jackson NO. (2016) Irresistible forces: facing up to demographics change, in P Spoonley (Ed.) Rebooting the Regions. Why low or zero growth needn’t mean the end of prosperity. Massey University Press: 49-77.

Jackson NO, L Brabyn, D Maré, MP Cameron and I Pool (2019) From ageing-driven growth towards the ending of growth. Subnational population trends in New Zealand, in J Anson, W Bartl, A Kulczycki (Eds.) Studies in the Sociology of Population. International Perspectives. Switzerland: Springer Nature: 161-193.

Jackson NO and MP Cameron (2017) ‘The unavoidable nature of population ageing and the ageing-driven end of growth - an update for New Zealand’ Population Ageing: 1-26. DOI: 10.1007/s12062-017-9180-8.

Johnson KM, LM Field and DL Poston Jnr (2015) 'More Deaths than Births: Subnational Natural Decrease in Europe and the United States'. Population and Development Review 41(4): 651–680.

Statistics New Zealand (2017) Subnational population projections, characteristics, 2013(base) -2043.