Why are mortality rates higher in Spain and Germany than in developing countries?

First of all, the low birth rate of the population is to blame, in countries such as Germany and Spain in the first place is not family and children, but a career and their own well-being, therefore not all residents are in a hurry to have children because of this, natural growth is disrupted in countries. there are more people who have died than have been born. While in other countries the birth rate is only growing, for example, China, which has a huge population, or Russia, which is taking measures to increase the birth rate through payments to families where a child is born, such support from the state helps the population grow.