The 1980 base population classified by sex and quinary age group up to age 85 and over is obtained from the population census conducted in June 1980. The figures are given in Census of Population 1980, Release No. 1, published by the Department of Statistics, Singapore.

The survival ratios are obtained from the 1979-81 Abridged Life Tables prepared by the author and published in “Increasing Life Expectancy in Singapore During 1969-1981”, Singapore Medical Journal 24 (1983). The values of the survival ratios, known as Px, for the various quinary age groups for each of the two sexes are computed from the values of the Lx column of the Abridged Life Tables.

The age-specific fertility rates and the gross reproduction rates are based on population data published in the above census report and on birth data published in the Report on the Registration of Births and Deaths for the year 1980. The female population by quinary age group and the births by similar age group of mothers are utilized to compute the age-specific fertility rate and the gross reproduction rates. The former rates are applied to the future female population in the reproductive ages to estimate the births that will occur in every five-year period.