The author reviews the major demographic trends of the twentieth century in Bulgaria.  "The results from the analysis show that the demographic development of Bulgaria especially in the years after 1950 differs very little from the developed, urbanized and industrialized countries.  The common features are:  development towards [replacement] fertility, [lower mortality rates], zero natural growth [leading] to an increasing life expectancy at birth, [and] population ageing...." (SUMMARY IN ENG AND RUS)