The study finds that growth is concentrated in the most metropolitan areas in the country and in the rural areas on which they have a strong influence, and diminished as the degree of rurality increases. [...] The concentration of newcomers in these regions helped increase the gap between these three areas and the rest of the country in terms of ethnocultural diversity. [...] To the extent that it plays a significant part in renewing the population and affects the age structure of populations, fertility is a key factor in the growth and dynamics of population aging. [...] Between the 1971 and 2001 censuses, the areas that had the strongest growth were either the most heavily populated metropolitan areas in the country or the rural areas that were classified in 2001 as having a strong MIZ. [...] Figure 2.3 shows the percentage variation of the population in the municipalities that give their name to the CMA (here called the “central municipalities”) and the population in the remaining municipalities of these CMAs (“peripheral municipalities”) for the nine CMAs with populations that surpassed 500,000 residents in 2001.