Around one-third1 of babies born in 2012 in the United Kingdom are expected to survive to celebrate their 100th birthday. A higher percentage of baby girls are expected to reach 100 than baby boys; 39 and 32 per cent respectively. At every age, females have more chance of reaching their 100th birthdays than males do.
However, for these percentages to be achieved, the assumptions about future mortality used in the 2010-based principal projection would need to be realised. The principal projection provides one set of results, but ONS also produces variant projections with different assumptions about future improvements in mortality. Table 1 gives the percentage of people projected to survive to age 100 from selected ages according to the principal, high life expectancy and low life expectancy variants. For example, 4.8 per cent of men turning 50 in 2012 are projected to survive to their 100th birthday in 2062 under the low life expectancy variant.
|Age in 2012||Population1 in 2012||Low Life Expectancy variant||Principal Projection||High Life Expectancy variant||Year age 100 is reached|
The table shows that for very young ages (20 and under) the difference between the low and high variant projections is very wide with the percentage of people surviving to their 100th birthday ranging from less than 10 per cent to 50 per cent and higher. This is because for these ages the 100th birthday will not be reached until 2092 or later, meaning that 80 or more years of assumptions about future mortality are included in the calculation. As with any projection into the future, the further from the projection base year the more uncertain the figures become. However, with the increase in age, the range between variants lessens since assumptions for fewer years are required; by age 80 the range between the low and high variants is less than 4 per cent.
Of the 395,000 men and 417,000 women aged 65 this year (2012), 10 and 14 per cent respectively are expected to survive to their 100th birthdays according to the principal projection. The low and high life expectancy variants illustrate the range of expected percentages surviving to 100, from 5 to 15 per cent for men aged 65 and from 9 to 20 per cent for women. How this translates into numbers is discussed in the next section.
This figure was calculated from the numbers of survivors in the lx column of the 2012 cohort life table from the 2010-based principal projection. (419.5 Kb Excel sheet)
Using the 2010-based principal projections for the population in 2012 and the numbers of survivors (lx) from the relevant life table1 we can estimate how many people of each age in 2012 are likely to survive to celebrate their 100th birthday. Figure 1 shows the numbers of people surviving to age 100 by their age in 2012, for each of the mortality variants.
The chart shows clearly the increase in the range of possible numbers of people surviving to age 100 as the projection is carried forward further into the future. In 2012 there are 826,000 babies aged under one year (principal projection); 423,000 boys and 403,000 girls. Of these, 135,000 men and 156,000 women are expected to still be alive by age 100 (in 2112) under the principal projection. However the numbers surviving to their 100th birthday could be as few as 19,000 men and 35,000 women (low life expectancy variant) or as many as 274,000 men and 278,000 women (high life expectancy variant).
There is a small peak in the chart for people aged 65 in 2012 - this relates to the post-war baby boom in 1947 when this age group was born. In 2012, the projected number of 65 year olds is 395,000 men and 417,000 women and, as mentioned above, around 10 per cent of men and 15 per cent of women of this age are expected to survive to age 100 (principal projection). That is, 37,000 men and 58,000 women aged 65 in 2012 are projected to survive to celebrate their 100th birthday in 2047 (principal projection). The low and high life expectancy variants illustrate other possible outcomes, with figures ranging from 21,000 to 61,000 for men and 38,000 to 81,000 for women surviving from age 65 to 100.
The chart displays a number of peaks and troughs that relate to rises and falls in fertility. The size of a birth cohort has an impact on the number of people surviving 100 years later. For example the peak at around age 45 in 2012 relates to the 1960s baby boom and the dip at around age 11 in 2012 relates to the low point in fertility in 2001.
The probability of surviving to age 100 has an impact on the number of people alive aged 100 or more. The mid-year population estimates of centenarians (people aged 100 years or more) has increased from just 600 in 1961 (first year for official mid-year population estimates) to nearly 13,000 in 2010 (latest mid-year estimate) and this is projected to rise to 456,000 by 2060 (principal projection).
Figures 2a, 2b and 2c show the numbers of centenarians by sex over different periods of time. Figure 2a shows centenarian data for 1961 to 2010 from the mid-year population estimates of the very elderly. Figure 2b shows equivalent data for 2010 to 2035 from the 2010-based national population projections and Figure 2c projections for 2035 to 2060. The charts have been displayed in this manner because the rapid growth in the number of centenarians both in estimates and projections means that much of the detail is lost when the numbers are plotted as a single time series.
In all charts the estimates and projections for female centenarians are higher than for males. The estimated number of female centenarians has risen from 500 in 1961 to more than 10,000 in 2010 and this figure is projected to reach 71,000 by 2035 and 276,000 by 2060 (principal projection). Males, although a lot lower in absolute numbers, have also experienced a rapid rise, from an estimated 92 centenarians in 1961 to just below 2,000 in 2010, and are projected to reach 39,000 by 2035 and 179,000 by 2060 (principal projection).
The charts showing projected numbers (Figures 2b and 2c) show the principal and the high and low life expectancy variant projections. In 2012 the projected numbers of centenarians from the three scenarios (principal, high life expectancy and low life expectancy) are similar, at around 2,500 men and 12,000 women. As the projection moves further into the future the range in the estimated numbers from the three scenarios widens, so that by 2035 there could be 26,000 (low), 39,000 (principal) or 57,000 (high) men and 55,000 (low), 71,000 (principal) or 91,000 (high) women aged 100 or more. These variant assumptions are intended as plausable alternatives to the principal assumptions and not to represent upper or lower limits.
In Figure 2b the projected numbers of centenarians are clearly higher for women in all three variants than for men. The projected number of women from the low life expectancy variant is higher than the projected number of men from the high life expectancy variant for most of the period 2010 to 2035, but this begins to change around 2035 and the lines cross over. Figure 2c shows more crossover between the different variants for males and females.
Population projections are not forecasts and do not attempt to predict the impact that future government policies, changing economic circumstances or other factors (whether in the UK or overseas) might have on demographic behaviour. They simply provide the population levels and age structure that would result if the underlying assumptions about future fertility, mortality and migration were to be realised.
All the figures quoted in this summary are cohort figures. Cohort life tables allow for known or projected changes in mortality rates during a person's lifetime. ONS also calculates period life tables. These are a useful measure of the mortality actually experienced for a given time period and provide an objective means of comparison of trends over time, between areas of a country and with other countries. For more information on the difference between period and cohort mortality please see the Guide to period and cohort life expectancy.
In addition to the principal assumptions, high and low variant assumptions are published for each of the three components of demographic change- fertility, life expectancy and migration. These variant assumptions are intended as plausible alternatives to the principal assumptions and not to represent upper or lower limits for future demographic behaviour.
Following the publication of the 2010-based period and cohort life expectancy tables, ONS prepares databases for the UK and each of the constituent countries containing mortality data used in the calculation of historic and projected life tables. Published for the first time as part of this release are tables of historic and projected qx (probability of dying at each age) and lx (numbers of people surviving at each age) values for the UK, on a period basis for each year 1951 to 2060 and cohort basis for each year of birth 1951 to 2060, for the principal projection and the high and low life expectancy variants.
Life table templates for the UK (principal, high and low variants) and constituent countries (principal projection only) that can be used to produce historic and projected life tables on a period or cohort basis by age and sex are available on request to email@example.com. Also available on request are tables of qx mortality rates for each of the UK constituent countries and for the principal, high and low variant projections.
Details of the policy governing the release of new data are available by visiting www.statisticsauthority.gov.uk/assessment/code-of-practice/index.html or from the Media Relations Office email: firstname.lastname@example.org
Principal variant: Annual improvements in mortality rates continue, converging to 1.2 per cent (for most ages) in 2035 (25 years from the base year) and this rate of improvement continues each year thereafter;
High variant: Annual improvements in mortality rates continue, converging to 2.4 per cent (for most ages) in 2035 (25 years from the base year) and this rate of improvement continues each year thereafter; and
Low variant: Annual improvements in mortality rates reduce, converging to 0 per cent (for most ages) in 2035 (25 years from the base year) and each year thereafter;
For more details see Mortality assumptions: 2010-based national population projections.