Population ageing is the issue debated in (West) Germany since the mid-seventies. When the 4th coordinated
population prospects (published in 1974) revealed the future ageing of population an interministerial
working group on population issues was founded under the responsibility of the Federal
Ministry of Interior. This interministerial working group prepared population prospects with different
fertility assumptions, fertility being rightly considered the main determinant of ageing. It did not foresee
an increase of life expectancy, the second determinant of ageing. And it was cautious as to immigration
of foreigners in the years after the recruitment stop in 1973; the three migration assumptions
were: zero, 20 000 annual net immigration and 55 000 annual net immigration