2. Results, 2010-Based National Population Projections

Introduction

This report provides a brief summary of the results of the 2010-based national population projections. It also provides additional charts and summary tables illustrating the results of the projections. For discussion of the results see the statistical bulletin. Included are sections on:

results,
the role of migration in population growth,
comparison with the results of the 2008-based national population projections,
charts for the UK and constituent countries are available in the appendices showing:
- actual and projected total population,
- actual and projected births and deaths,
-  percentage age distribution of the population,
-  actual and projected total population for the principal and key variant projections,
-  change in the projected population at 2035 by age and sex compared with the 2008-based projections.

Results

The UK population is projected to increase gradually from an estimated 62.3 million in 2010 to reach 73.2 million by 2035. Of the projected 10.9 million increase between 2010 and 2035, approximately 5.8 million (53 per cent) is due to projected natural increase (more births than deaths) while the remaining 5.1 million (47 per cent) is the assumed total number of net migrants.

Summary results tables

Table 2-1 presents a summary of the projection results by components of change from 2010 to 2035, for the UK. The equivalent tables for the constituent countries of the UK, England & Wales and Great Britain can be found in the data download of this table.

Table 2-1

Components of change: summary (annual average), United Kingdom, 2010-2035

thousands
	2010-11	2011-16	2016-21	2021-26	2026-31	2031-35
Population at start	62,262	62,735	65,271	67,636	69,820	71,766
Births	811	840	832	813	797	804
Deaths	559	557	559	576	607	643
Natural change	251	283	273	237	189	161
Migration	222	224	200	200	200	200
Total change	473	507	473	437	389	361
	————	————	————	————	————	————
Population at end	62,735	65,271	67,636	69,820	71,766	73,208

Table source: Office for National Statistics

Table notes:

Figures may not sum due to rounding

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Charts of summary results

This section presents charts for the UK for the period 1971 to 2085. The equivalent charts, for the period 1971-2060, for the constituent countries of the UK are available in the appendices A to D.

Figure 2-1

Actual and projected total population, United Kingdom, 1971-2085

Source: Office for National Statistics

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Figure 2-2

Figure 2-3 shows how the age distribution of the UK is projected to change, illustrating how the median age of the population increases through the projection period.

Figure 2-3

Percentage age distribution, United Kingdom, 1971-2085

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Variant projections

Table 2-2 presents projections of the total population under the principal projection, standard variant projections and special case scenarios for the UK and its constituent countries in 2035, 2060, 2085 and 2110. Three additional measures available in the data download include: the percentage of the population under 16, percentage of population 65 and over, and dependants per 1,000 persons of working age.

Table 2-2

Measures of population structure under the principal projection, standard variant projections and special case scenarios, UK, 2035, 2060, 2085 and 2010

Projection	2035	2060	2085	2110
Principal projection	73,208	81,481	89,300	96,979

Single Component Variants
High fertility	75,048	87,050	100,533	115,579
Low fertility	70,832	75,380	78,277	80,395
High life expectancy	73,920	84,637	95,522	106,843
Low life expectancy	72,467	78,181	82,777	86,686
High migration	75,135	85,811	96,120	106,178
Low migration	71,280	77,152	82,480	87,780

Combination Variants
(largest/smallest total population size)
High fertility, High life expectancy, High migration	77,746	94,817	114,471	136,791
Low fertility, Low life expectancy, Low migration	68,215	68,021	65,879	63,415

Special Case Scenarios
Zero migration (natural change only)	65,740	64,073	60,813	57,861

Table source: Office for National Statistics

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Figure 2-4 shows the estimated and projected population for the principal projection and selected variant projections for the UK between 1981 and 2085. Charts for the constituent countries of the UK, (all for the period 1971-2060) can be found in Appendices A to D.

Figure 2-4

Actual and projected total population, United Kingdom, 1981-2085

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The role of migration in population growth

The population of the UK is projected to rise; both because of positive natural change, that is, more births than deaths and because of positive net migration. However, the components of population change are not independent of each other. In particular, the projected numbers of future births and deaths are themselves partly dependent on the assumed level of net migration.

An understanding of the overall effect of migration on population growth can be obtained by comparing the results of the principal and main variant projections with those of the zero net migration ('natural change only') variant projection. The zero net migration variant assumes that net migration will be zero at all ages in future, but makes the same assumptions about fertility and mortality as the principal projection. In the analysis below, the effect of net migration on population growth in the period to 2035 is considered.

If annual net inward migration to the UK was to average 200,000 a year (the long-term assumption in the principal projection) this would lead to a total net inflow of five million migrants in the period between 2010 (the base year of the projections) and 2035. In fact, the projected total number of net migrants during this period in the principal projection is slightly higher (5.1 million) due to the higher migration assumptions for the first few years of the projection.

The assumed fertility and mortality rates are the same in the principal projection, the zero net migration variant projection and the high and low migration variants. However, because migration is concentrated at young adult ages, the different assumed numbers of migrants affect the number of women of childbearing age and hence the future number of births.

There is no comparable effect on deaths, at least in the period to 2035. At ages over 45, assumed net migration flows are close to zero in the principal projection and the high and low migration variants. Indeed, small net migration outflows are assumed at some older ages. So the projected number of deaths over the period to 2035 is similar under all the migration variants.

Table 2-3 shows the projected components of population change in the period to 2035 in the principal projection, the high and low migration variants (which assume long-term annual net inward flows of 260,000 and 140,000 a year respectively), and the zero net migration variant projection.

Table 2-3

Projected population change, United Kingdom, 2010-2035

thousands
	High migration variant	Principal projection	Low migration variant	Zero net migration variant
Population at mid-2010	62,262	62,262	62,262	62,262

Population change (2010-35)
Births	20,931	20,436	19,942	18,087
Deaths	14,671	14,635	14,598	14,609
Natural change	6,259	5,802	5,344	3,478
Net migration	6,614	5,144	3,674	0
Total change	12,873	10,946	9,018	3,478

Population at mid-2035	75,135	73,208	71,280	65,740

Table source: Office for National Statistics

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Table 2-4 shows how the projected population growth is broken down between the assumed level of net migration and projected natural change.

Table 2-4

Projected population growth by component, United Kingdom, 2010-2035

thousands
	High migration variant	Principal projection	Low migration variant
Total population increase between 2010 and 2035	12,873	10,946	9,018
Resulting from:
Assumed net migration	6,614	5,144	3,674
Natural change assuming zero net migration	3,478	3,478	3,478
Additional natural change from assumed level of net migration	2,781	2,324	1,866

Table source: Office for National Statistics

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In the principal projection, the population of the UK is projected to grow by 10.9 million between 2010 and 2035. Some 5.1 million of this increase is directly due to the assumed number of net migrants. Natural change accounts for a further 5.8 million - the difference between 20.4 million births and 14.6 million deaths. Some 3.5 million of this natural change (increase) would occur with zero net migration. The remaining 2.3 million is the net effect of the assumed annual level of net migration on natural change (almost entirely the effect on births).

Some 47 per cent of population growth in the principal projection is therefore directly attributable to the assumed number of net migrants. The remaining 53 per cent is attributable to projected natural change (of which 32 per cent would occur with zero net migration and 21 per cent arises from the effect of net migration on natural change). In total, therefore, some 68 per cent of population growth in the period to 2035 in the principal projection is attributable, directly or indirectly, to future net migration.

It should be emphasised that these calculations are based on comparing alternative projections which make the same assumptions about future fertility and mortality rates irrespective of the assumed level of net migration. In practice, fertility and mortality rates for new migrants are likely to differ, to some extent, from those for the existing population.

Notes for The role of migration in population growth

The principal projection and the zero net migration variant projection for the UK are calculated by aggregating equivalent projections for the four constituent countries of the UK. The resulting UK level fertility and mortality rates are therefore effectively weighted averages of those for the individual countries. This leads to some very small differences at UK level between the effective fertility and mortality rates used in the principal projection and the zero net migration variant. This has no significant effect on the analysis in this section.

Comparisons with the 2008-based national projections

Base population

Overall, the published mid-2010 population estimate for the UK is 40,000 (0.06 per cent) higher than the 2008-based projection of the population at mid-2010.

Projected future population

The projected population of the UK at 2035 is about 924,000 (1.3 per cent) higher than in the 2008-based projections. This is due an increase in the assumed number of births and net migration.

Populations are higher than in the 2008-based projections for England, Wales, and Scotland but lower for Northern Ireland. The percentage difference by 2035 is greatest for Scotland (3.6 per cent) where the assumed level of fertility and net migration has risen. The projected populations of England and Wales are 1.2 per cent and 0.1 per cent higher respectively than in the 2008-based projections. The population of Northern Ireland is projected to be 1 per cent lower than previously.

Compared with the previous projections, the UK population at 2035 is higher in all age groups apart from the 75 and over age group.

Comparisons with the previous (2008-based) projections are given in Tables 2-5 and 2-6 and illustrated in Figure 2-5.

Table 2-5