This study presents a simple method for modeling future mortality of an insured population from external information, in case of insufficient historical data. Thus, with a parametric adjustment, an assumption on the form of changes in the level of mortality (linear or exponential evolution) and an expert opinion on the generational life expectancy at a given age, this work presents the construction of a complete mortality table taking into account future mortality improvement. An example implementation is presented with data of the insured population of sub-Saharan Africa francophone.