The Resource Flows survey consists of two complementary questionnaires: one for donors and one for developing countries and countries in transition. Data on donor expenditures for population and AIDS activities are collected through a donor survey and supplemented with data extracted from the OECD/DAC Creditor Reporting System. The developing countries and countries in transition survey is used to collect data on domestic funding for population and AIDS activities. Both surveys are conducted annually, but developing countries and countries in transition surveys are performed on a rotating sample basis.