On a national scale or place, the population can increase or diminish, besides for the natural movements, for the migratory movements, which are the human displacements of long duration of a place of origin to other one of destination. Inside the migratory movements we can distinguish two principal components depending on if the subject goes to a place or goes out of him. This way when the individual leaves his place of origin it is assessed as emigrant, whereas when it comes to the place of destination she is considered to be an immigrant. The third component exists inside the migrations, which one produces when individuals emigrated return spent a time to his place of origin, naming them returned
