MUTAŢII STRUCTURALE ALE POPULAŢIEI PE GRUPE DE VÂRSTĂ ŞI RISCURILE ASOCIATE
ABSTRACT. – Structural Mutations of Population on Age Groups and the Associated Risks. During the process of demographical transition, at the level of a society, two situations appear that imply multiple risks, but are differentiated from a phase to another: the powerful increase of the young population ratio, respectively the increasing of the degree of population ageing. The fast increase of the young group weight is produced in the second phase of the demographical transition, on the basis of maintaining a very high birth rate and of the death rate decreasing, especially of the child death rate. It is specific for the underdeveloped societies, with a population of a progressive type and with the age pyramid in a triangular form (the hope of life at the birth being still reduced). The most of the African states are to be found in this situation (in more than 80 - % of them the weight of population under 15 years of age being of 41-49 %), and a great part of those from Meridional Asia and the Central America. The process of demographical ageing is affecting the majority of the European states and Japan (with a weight of population of and exceeding 65 years between 13 and 17 %). It is directly caused by the existance of a decreased birth rate for a long period and by the increase of the average life length, defining phenomena for the posttraditional phase. Also, it is a result of the massive emigration (especially of a rural migration). The appreciation of the pressure exercised by the dependent population (mainly young and old) is done through the dependence ratio depending on the age.