The aging of the population is a concept of demography with great importance in the economic study. It focuses on the analysis of the change that takes place in the population according to their different age ranges, from an initial presence of predominantly young individuals to a later situation of most older individuals.
The phenomenon of population aging corresponds to the different changes of sociological and economic nature that humanity has experienced over the years. By definition, this fact implies the increase in the proportion of the elderly (over 60 years old) with respect to the total citizenship.
In that sense, it should be noted that, as access and quality of health services are becoming better, people extend their life expectancy and, therefore, the volume of older individuals in society increases . All this has been demonstrated in demographic studies.
To the increase in life expectancy that has been established, we must add the decrease in the birth rate in the more developed countries , which means that there is no replacement in the number of young people that can compensate for aging.
In many of these places, as in the case of Spain , this fact has been offset by the immigrant population, whose rates are still higher in terms of descent.
In that sense, it is worth mentioning the phenomenon of migration as another important element to take into account together with mortality and birth rates, since people who migrate in search of opportunities usually correspond to young age groups.
As an instrument of representation and analysis, the population pyramid is used, a kind of horizontal bar chart that, through different measures or lengths, shows the population proportions of a country or region, both at the age and sex levels. In this way, the different sections mentioned above are easily observable and measurable.
An example of population aging can be easily seen in a population pyramid of Spain between 2009 and 2049: