Age structure
Average age rose to 38.6 years in 2004
Population: by age, UK
The age structure of the UK population has become older in the last three decades, and is likely to become older still in the next three decades. The median age rose from 34.1 years in 1971 to 38.6 in 2004 and is projected to rise to 42.9 in 2031.
The proportion of the population aged under 16 is declining due to sustained low fertility. In 1971 over 25 per cent of the population were aged under age 16. This fell to 19 per cent in 2004 and is projected to fall further to 17 per cent by 2031.
At the same time, the proportion of older people is increasing. The percentage of people over state pension age increased from 16 per cent in 1971 to 19 per cent in 2004. Even allowing for the rise in state pension age for women to 65 being phased in between 2010 and 2020, the proportion of people over state pension age is projected to rise to 23 per cent in 2031. The most substantial growth has occurred among the oldest old – those aged 85 and above. The proportion of the UK population aged 85 or over has more than doubled from 0.9 per cent in 1971 to 1.9 per cent in 2004.
The increase in older people is a result of the relatively high number of births that occurred in the first two decades of the 20th century, combined with increased longevity at older ages. The rising proportion of the oldest old in particular has significant implications in terms of welfare, health and social support.
Age structure indicators, UK
It is useful to relate these population groups in terms of dependency of the old and young on the population of working-age. In 1971 there were 43.8 children and 28.0 older people per hundred people of working age. By 2004 the number of children (aged under 16) per hundred working-age people had fallen to 31.4. This fall reflects both the smaller number of children in 2004 relative to 1971 and the increase in the working-age population, which was due to the 1960s baby boomers who joined the working-age population from the late 1970s.
It is because of this increase in the population of working age that the old-age dependency ratio only increased slightly between 1971 and 2004, reaching 30.0 per hundred working-age people. The ageing index, which is the ratio of older people to children, rose sharply from 64 .0 in 1971 to 95.5 in 2004.
Sources: Age structure up to 2004: Population Estimates, Office for National Statistics; General Register Office for Scotland; Northern Ireland Statistics and Research Agency Age structure for 2031: population projections, Government Actuary’s Department
Notes: The population aged above state pension age refers to men aged 65 and over and women aged 60 and over.
The working-age population refers to men aged 16 to 64 and women aged 16 to 59. By 2031 pension age will have gone up to 65 for women and the projected data for 2031 reflect this change.
The dependency ratio and the ageing index are based on age alone and do not take account of economic dependence.