For migration a range of administrative records and population census are used. The national population projections are made by the cohort-component method. The components are births, and deaths. Projections are made in five-year cycles. Each cycle is independent of the preceding one.
Assumptions concerning the components are constant during each five-year cycle.
It also makes projections by single years and has other options. Release 11.0 is written in four languages including English and Turkish. For more information or a copy of the software, apply to the Center for Population and Demographic Analysis, State Institute of Statistics, or to the Population Council, One Dag Hammarskjold Plaza, New York, NY 10017. The sub-national population estimates are made by the apportionment method. It relies on the rate of increase.