6 Results
6.1 Trends in age structure and health
We look briefly at trends in age structure and health. Table 8 shows estimates and projections for life expectancy. The projections are based on the assumption that, across both sexes and all ages, mortality rates decline at 1.5% per year, which is approximately the historical average (see Section 5.1.1). Under this assumption, life expectancy increases to 86.3 years by 2051. The projected extension in life expectancy between 2002 and 2051 turns out to exactly equal the actual extension in life expectancy between 1951 and 2002, at 8.6 years. Statistics New Zealand, like most official statistical agencies, assumes that gains in life expectancy will slow in the coming decade: their projected life expectancy for 2051 is only 84.5 years[7]. A growing number of academic demographers, however, question the assumption that gains in life expectancy will slow (Oeppen and Vaupel 2002). Sensitivity tests, not shown here, indicate that if mortality rates were to decline at 1.0% per year, life expectancy in 2051 would be 83.8 years. Conversely, if rates were decline at 2.0% per year, life expectancy in 2051 would be 88.9 years.
| 1951 | 2002 | 2026 | 2051 | |
|---|---|---|---|---|
| Life expectancy (years) | 69.1 | 77.7 | 82.3 | 86.3 |
Note – Calculations assume that mortality rates decline at 1.5% per year after 2002.
Increases in life expectancy, combined with the ageing of the baby boom cohorts, lead to substantial increases in the population share of older age groups, as indicated by Table 9. Under the assumptions used, the population share of disabled people and decedents (ie people in their last year of life) increases much less dramatically. The finding that the population shares of the aged rise more quickly than the population shares of people with disabilities and decedents is preserved under quite different assumptions about disability and mortality rates. For instance, even if disability rates by age and sex are were to remain constant, the population share of people with disabilities would only rise to 18% in 2051.
| Estimate | Projection | ||||
|---|---|---|---|---|---|
| Percent of population | 1951 | 1976 | 2002 | 2026 | 2051 |
| Age 65 and over | 9.0% | 8.8% | 11.9% | 17.9% | 24.1% |
| Age 85 and over | 0.3% | 0.6% | 1.3% | 2.4% | 5.5% |
| Disabled | 10.1% | 10.2% | 12.0% | 12.6% | 13.1% |
| 0.9% | 0.8% | 0.7% | 0.8% | 1.0% | |
Notes – Calculations assume that disability rates constant until 2002, and begin declining at 0.5% per year from that time. Mortality rates are assumed decline at 1.5% per year after 2002.
Notes
- [7]This is the ‘median’ assumption, from the 2001-base projections, available at www.stats.govt.nz.
