For some years - and in many countries - an attempt has been made to become acquainted with the financial aspirations of individuals and to measure their psychological needs. In order to do this, the same question is regularly asked of samples of the population and the responses, which become meaningful through a comparison of the results of repeated surveys, are studied. But the answers thus obtained are difficult to analyse. Actually, a diversity of factors determine them and it is a tricky job to isolate their respective effects. Also, the availability of such a long series of statistical data such as those which IPOP has is bound to provide a great deal of information to those studying problems of this kind.