### 3. The Method Used for Projecting Population

The cohort component method is used for Population Projections with assumptions made for components of population change, namely population process components, birth, death and international migration. Assumptions are made based on actual statistics of each component using the demographic projection method.

## (1) Summary of Assumptions for Future Fertility

Assumptions were made for both marriage and birth index of female cohorts born in 1995 (reference cohorts) and that the transition would gradually take place from the actual figures of elderly cohorts or statistically assumed figures through the assumptions of the reference cohorts to those of cohorts born in 2010, and then remain flat thereafter.

Type of assumption	Fertility assumption index	Presupposition	Total fertility rate	Projection in Dec. 2006
Actual current figure of generation born in 1960	Assumption for generations born in 1995 (reference cohort)	2010 Actual figure	Interim	2060	2055
Medium-variant assumption	(1) Average age of first marriage(2) Proportion of never-married(3) Number of live births by a married-couple(4) Effects of divorce, bereavement, and remarriage	25.7	→	28.2	1.39	Maximum 2013 1.39	1.35	1.26
9.4%	→	20.1%
2.07	→	1.74	Minimum 2024 1.33
0.962	→	0.938
High-variant assumption	(1) Average age of first marriage(2) Proportion of never-married(3) Number of live births by a married-couple(4) Effects of divorce, bereavement, and remarriage	Same as above	→	27.9	1.39	Maximum 2020 1.61	1.60	1.55
→	14.7%
→	1.91	Minimum 2010 1.39
→	0.937
Low-variant assumption	(1) Average age of first marriage(2) Proportion of never-married(3) Number of live births by a married-couple(4) Effects of divorce, bereavement, and remarriage	Same as above	→	28.5	1.39	Maximum 2010 1.39	1.12	1.06
→	26.2%
→	1.57	Minimum 2023 1.09
→	0.938

Sex ratio for live birth: Sex ratio for live birth from 2006 to 2010 was set to a constant value (105.5).

## (2) Summary of Assumptions for Mortality

“Medium-variant of death” assumption (2060: male 84.19 years, female 90.93 years) was made according to the actual mortality figures from 1970 to 2010 and “high-variant death” assumption (2060: male 83.22 years, female 89.96 years) and “low-variant death” assumption (2060: male 85.14 years, female 91.90 years) based on the confidence interval of mortality index parameters.

Life expectancy at birth	Actual figure 2010	Medium-variant death assumption 2060	Projection in December 2006 2055
Male	79.64 years	84.19 years	83.67 years
Female	86.39 years	90.93 years	90.34 years

## (3) Outline of Assumptions on International Migration

The average rate of annual net migration of Japanese by age and sex during the period between 2004 and 2009 was set to a constant value. With foreign nationals, the assumptions were made for the net migration by reflecting the trend since 1970. Departure excess was observed with both males and females in 2011, the year affected by the Great East Japan Earthquake, but entry exceeded departure in 2012. The average rate of annual net migration of foreign nationals in 2030 is assumed to be 34,000 males and 38,000 females and to remain unchanged thereafter.