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Projected Population of Scotland (2010-based)

Annex B Mortality assumptions

The mortality rates for the first year of the projection, mid-2010 to mid-2011, are based on the best estimates that could be made in the autumn of 2011 of the numbers of deaths at each age in 2010-11.

Assumed improvements in mortality rates after 2010-11 are based on trends in mortality rates before 2010. Improvements in mortality rates by age and gender in the base year of the projection are estimated from the trends in years from 1961 to 2009. It is assumed that annual rates of mortality improvement will converge to a common rate of 1.2 per cent per year at 2035 for most ages, and continue to improve at that constant rate thereafter. However, it is assumed that those born in the years 1925 to 1938 (cohorts which have consistently experienced relatively high rates of mortality improvement over the last 25 years) will continue to experience higher rates of mortality improvement until they die, with assumed rates of improvement in and after 2035 rising from 1.2 per cent a year for those born after 1938 to a peak of 2.5 per cent a year for those born in 1931 and 1932 then declining back to 1.2 per cent a year for those born in 1924, and lower rates for those born earlier.

A comparison of period expectations of life (Eols) for Scotland with the UK as a whole (Figure B1) suggests there has been a gradual widening in the difference in expectations of life for males under the age of 80, since the early 1980s. There have also been increases in divergence for females since 2000 (Figure B2).

Figure B1 Period expectations of life (Eol) for Scotland less respective expectation of life for UK - for males at birth and ages 20, 40, 60 and 80, 1983-2010

Figure B1 Period expectations of life (Eol) for Scotland less respective expectation of life for UK - for males at birth and ages 20, 40, 60 and 80, 1983-2010

Figure B2 Period expectations of life (Eol) for Scotland less respective expectation of life for UK - for females at birth and ages 20, 40, 60 and 80, 1983-2010

Figure B2 Period expectations of life (Eol) for Scotland less respective expectation of life for UK - for females at birth and ages 20, 40, 60 and 80, 1983-2010

Although there has been decreases in the differentials between Scotland and the UK in 2008 and 2009, this is not sufficient evidence to suggest a change in the overall trend. Therefore, following further analysis (and as similarly done in previous sets of projections), lower rates of improvement were adopted in Scotland for males aged 27 to 59 and 66 to 95, and for females aged 28 to 41 and 65 to 92, than for the UK as a whole. At all other ages the UK levels have been used. By 2035 all improvement rates are projected to converge to the same annual rates of improvement as for the UK.

The impact of these new assumptions can be summarised using the period expectation of life at birth, based on the mortality rates for the given year. Life expectancy is assumed to rise from 75.8 years in 2009 to 80.9 years in 2035 for men, and from 80.3 years in 2009 to 85.1 years in 2035 for women. Compared with the assumptions used in the 2008-based projections for Scotland, the life expectancy for men in 2035 is the same for both sets of projections, but for women it is 0.3 years lower in the 2010-based projections.

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